Journal of Food Science and Engineering 7 (2017) 479-496 doi: 10.17265/2159-5828/2017.10.003

Shear Rate Effect on the Viscosity of Homemade and

Commercial Tomato Sauce

Virues-Delgadillo Jorge-Octavio, Lozada-Santillan Claudia-Karina, Bulbarela-Sampieri Carmen, Galán-Méndez Frixia and López-del-Castillo-Lozano Micloth Facultad de Ciencias Químicas, Universidad Veracruzana, Lomas del Estadio S/N, Xalapa, Veracruz 91000, México

Abstract: Rheological characterization of tomato products is important not only for design of unit operations, but also to optimize processes and guarantee high quality of food products. Time dependence is related with structural changes due to shear rate. Thus, rheological characterization as a function of time is extremely important to understand the changes that occurred in food products during commercial processes. However, these characterizations are rare in the literature for tomato products. Those rheological properties depend of several parameters, such as agronomic, structural and process parameters. In this study, the effect of shear rate on the viscosity at room temperature (22 °C) of two kinds of tomato sauce (homemade and commercial) is analyzed; using a Brookfield viscometer model 4535, Lab-Line Instruments. Homemade sauce was prepared with fresh saladette tomatoes from a local market. Rheological analysis was performed at shear rates from 0.05 to 10.47 s-1; using all the spindles available. Statistical analysis was made using LSD and Duncan tests with a confidence interval of 95% (p-value of 0.05). It was demonstrated that homemade and commercial tomato sauce behaved as a thixotropic fluid, due to the typical decrease on viscosity samples observed when testing time was increased. When tomato sauce is at rest, it has a gelled tridimensional structure; and, as soon as a shear stress is applied, the movement generates an alignment of tomato constituent chains in flow direction, breaking physic entanglements and thus causing a decrease in viscosity as a function of time. Furthermore, it was discovered that the viscosity of homemade sauce was higher than the viscosity of commercial sauce. The latter may be due to the pre-thermal treatment. During this unit operation, polymeric chains of lycopene most likely break into smaller chains of isoprene, causing the observed decrease in viscosity. Besides, commercial sauce contains additives, seasonings, preservatives and thickeners that are not in a homemade sauce. Key words: Food rheology, viscosity, shear rate, tomato sauce.

1. Introduction

Tomato is one of the most consumed vegetables over the world [1], which represents an essential product on human diet, and a rich nutritional resource on vitamin C, potassium and anti-oxidants like licopene [2]. Food industry has developed endless tomato based products, such as sauces, purees, juices, concentrates, etc. In order to maintain the quality of these products and guarantee its shelf durability, industries rely on chemical and physical techniques that enable them to know the status of the product and at the same time helping them to streamline the

Corresponding author: Virues-Delgadillo Jorge Octavio,

PhD in chemical & biological engineering, full time professor, research fields: food rheology and biomaterials mechanical testing.

production process. Techniques for measuring the rheological properties of food fluids were used for 30 years [3, 4]; although most current efforts to measure the rheological behavior of fluids include work of Rao [5], Steffe [6] and Roudot [7]. Rheological characterization of tomato products is important not only for the design of unit operations, but also for optimization processes and quality assurance of food products [8, 9]. Available information found in the literature is variable and is only concentrated on measurements of steady state shear [10]. Many studies only focus on the measurement of a condition or are empirical methods of evaluation. Time dependence is related to structural changes due to shear flow [11]. Consequently, time-dependent rheological characterization is extremely important in order to

D DAVID PUBLISHING

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

480

understand the changes that occur in the product during a commercial process. However such characterizations are rare in the literature for tomato products [8-10, 12-16]. The rheological properties of tomato products depend on several number of parameters, such as agronomic parameters (variety and maturity), compositional parameters (soluble solids, acidity and pectin content) and process parameters (finished product appearance and heat treatment) [13, 17].

2. Methodology

In order to perform viscosity tests, Saladette tomatoes and commercial tomato sauce was used, which were purchased at a local supermarket. The equipment used to measure the viscosity (Fig. 1) was a Brookfield Viscometer (Model 4535, Lab-Line Instruments), blender, beaker (600 mL), stopwatch, spindle number from two until seven (Fig. 2). Diameter of Brookfield spindles is shown in Table 1. Saladette tomatoes were purchased for making homemade sauce. The tomatoes were washed with soap and water, before being chopped and then crushed in a blender (Oster brand). Homemade and commercial tomato sauces were analyzed by triplicate. Viscosity and shear stress of homemade and commercial sauce were determined using all different spindles available in the range from 0.05 to 10.47 s-1. The temperature in this study was maintained constant (room temperature of 22 °C). Statistical ANOVA tests were performed using SPSS 16.0 software, where Duncan subgroups obtained are shown in Table 2 (for thixotropic analysis) and Table 3 (for type of sauce viscosity behavior).

3. Results

In this paper the time-dependent rheological behavior of homemade and commercial tomato sauce at different shear rates was analyzed. Thixotropic behavior was found when the specimens were loaded and un-loaded at each shear rate tested, as shown in

Fig. 1 Typical tomato sauce specimen analyzed on Brookfield viscometer.

Fig. 2 Brookfield spindle numbers and geometry.

Table 1 Diameter of Brookfield spindles.

Spindle Nr. Diameter (cm) 2 4.7 3 3.5 4 2.7 5 2.1 6 1.5 7 0.2

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

481

Table 2 Duncan ANOVA results that demonstrate thixotropic behavior.

Group Combination Mean viscosity (cP) p-value

1 Unload, Spindle 6, Shear 1.05 Load, Spindle 6, Shear 1.05

1,341.667 1,416.667 0.394

2 Load, Spindle 6, Shear 1.05 Unload, Spindle 6, Shear 0.26

1,416.667 1,580.000 0.640

3 Unload, Spindle 6, Shear 0.26 Unload, Spindle 6, Shear 0.52

1,580.000 1,600.000 0.820

4 Load, Spindle 6, Shear 0.52 2,170.000 1.000 5 Load, Spindle 5, Shear 1.05 2,820.769 1.000

6 Unload, Spindle 5, Shear 1.05 Load, Spindle 6, Shear 0.26

3,013.750 3,027.273 0.878

7 Load, Spindle 4, Shear 1.05 3,377.143 1.000

8 Unload, Spindle 5, Shear 0.52 Load, Spindle 5, Shear 0.52

3,690.909 3,830.833 0.112

9 Unload, Spindle 4, Shear 1.05 Load, Spindle 3, Shear 1.05

4,083.636 4,196.923 0.198

10 Unload, Spindle 5, Shear 0.26 4,493.636 1.000 11 Unload, Spindle 3, Shear 1.05 4,900.667 1.000 12 Load, Spindle 5, Shear 0.26 5,097.273 1.000

13 Load, Spindle 4, Shear 0.52 Unload, Spindle 4, Shear 0.52

5,929.091 6,010.000 0.358

14 Load, Spindle 3, Shear 0.52 Unload, Spindle 3, Shear 0.52

7,005.455 7,085.714 0.361

15 Unload, Spindle 4, Shear 0.26 10,079.00 1.000 16 Load, Spindle 4, Shear 0.26 10,673.00 1.000 17 Unload, Spindle 3, Shear 0.26 11,100.00 1.000 18 Load, Spindle 3, Shear 0.26 12,048.18 1.000

Table 3 Duncan ANOVA results of homemade (Type 1) and commercial (Types 2 and 3) tomato sauce specimens.

Group Combination Mean viscosity (cP) p-value 1 Type 1, Spindle 5, Shear 0.05 73,085.00 1.000 2 Type 3, Spindle 4, Shear 0.05 50,800.00 1.000 3 Type 1, Spindle 6, Shear 0.05 45,450.00 1.000 4 Type 1, Spindle 3, Shear 0.05 41,666.67 1.000

5 Type 1, Spindle 4, Shear 0.05 Type 2, Spindle 4, Shear 0.05

37,546.67 36,436.67 0.092

6 Type 1, Spindle 5, Shear 0.10 32,660.00 1.000 7 Type 3, Spindle 4, Shear 0.10 26,218.00 1.000 8 Type 1, Spindle 3, Shear 0.10 24,421.43 1.000 9 Type 2, Spindle 3, Shear 0.10 22,890.00 1.000 10 Type 2, Spindle 4, Shear 0.10 21,225.00 1.000

11 Type 3, Spindle 5, Shear 0.05 Type 1, Spindle 6, Shear 0.10

19,622.00 19,283.33 0.607

12 Type 1, Spindle 4, Shear 0.10 Type 1, Spindle 5, Shear 0.26

16,130.00 15,183.00 0.151

13 Type 3, Spindle 3, Shear 0.26 Type 3, Spindle 4, Shear 0.26 Type 1, Spindle 3, Shear 0.26

13,570.67 12,466.67 12,287.69

0.065

14

Type 3, Spindle 4, Shear 0.26 Type 1, Spindle 3, Shear 0.26 Type 2, Spindle 3, Shear 0.26 Type 1, Spindle 6, Shear 0.26

12,466.67 12,287.69 12,048.18 11,380.00

0.134

15 Type 1, Spindle 6, Shear 0.26 Type 2, Spindle 4, Shear 0.26

11,380.00 10,673.00 0.283

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

482

(Table 3 continued)

Group Combination Mean viscosity (cP) p-value

16 Type 2, Spindle 4, Shear 0.26 Type 1, Spindle 2, Shear 0.26

10,673.00 9,853.50 0.214

17

Type 1, Spindle 2, Shear 0.26 Type 2, Spindle 5, Shear 0.05 Type 3, Spindle 5, Shear 0.10 Type 3, Spindle 3, Shear 0.52

9,853.50 9,210.00 8,652.00 8,510.80

0.062

18

Type 2, Spindle 5, Shear 0.05 Type 3, Spindle 5, Shear 0.10 Type 3, Spindle 3, Shear 0.52 Type 1, Spindle 5, Shear 0.52

9,210.00 8,652.00 8,510.80 8,092.73

0.123

19

Type 3, Spindle 5, Shear 0.10 Type 3, Spindle 3, Shear 0.52 Type 1, Spindle 5, Shear 0.52 Type 2, Spindle 6, Shear 0.05

8,652.00 8,510.80 8,092.73 7,666.67

0.176

20

Type 3, Spindle 3, Shear 0.52 Type 1, Spindle 5, Shear 0.52 Type 2, Spindle 6, Shear 0.05 Type 3, Spindle 4, Shear 0.52

8,510.80 8,092.73 7,666.67 7,189.17

0.066

21

Type 1, Spindle 5, Shear 0.52 Type 2, Spindle 6, Shear 0.05 Type 3, Spindle 4, Shear 0.52 Type 2, Spindle 3, Shear 0.52 Type 1, Spindle 3, Shear 0.52 Type 1, Spindle 6, Shear 0.52 Type 1, Spindle 4, Shear 0.26 Type 3, Spindle 5, Shear 0.52 Type 2, Spindle 5, Shear 0.10

8,092.73 7,666.67 7,189.17 7,005.45 6,950.83 6,940.00 6,805.00 6,710.00 6,628.00

0.060

22

Type 3, Spindle 4, Shear 0.52 Type 2, Spindle 3, Shear 0.52 Type 1, Spindle 3, Shear 0.52 Type 1, Spindle 6, Shear 0.52 Type 1, Spindle 4, Shear 0.26 Type 3, Spindle 5, Shear 0.52 Type 2, Spindle 5, Shear 0.10 Type 2, Spindle 5, Shear 0.10 Type 2, Spindle 4, Shear 0.52

7,189.17 7,005.45 6,950.83 6,940.00 6,805.00 6,710.00 6,628.00 5,929.09 5,772.50

0.070

23

Type 3, Spindle 5, Shear 0.52 Type 2, Spindle 5, Shear 0.10 Type 2, Spindle 4, Shear 0.52 Type 3, Spindle 5, Shear 0.26 Type 3, Spindle 3, Shear 1.05 Type 1, Spindle 2, Shear 0.52

6,710.00 6,628.00 5,929.09 5,772.50 5,252.08 5,243.86

0.050

24

Type 2, Spindle 4, Shear 0.52 Type 3, Spindle 5, Shear 0.26 Type 3, Spindle 3, Shear 1.05 Type 1, Spindle 2, Shear 0.52 Type 1, Spindle 5, Shear 1.05 Type 2, Spindle 5, Shear 0.26

5,929.09 5,772.50 5,252.08 5,243.86 5,145.83 5,097.27

0.279

25

Type 3, Spindle 3, Shear 1.05 Type 1, Spindle 2, Shear 0.52 Type 1, Spindle 5, Shear 1.05 Type 2, Spindle 5, Shear 0.26 Type 3, Spindle 4, Shear 1.05 Type 3, Spindle 5, Shear 1.05 Type 2, Spindle 3, Shear 1.05 Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52

5,252.08 5,243.86 5,145.83 5,097.27 4,298.50 4,267.92 4,196.92 3,860.00 3,830.83

0.069

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

483

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

26

Type 1, Spindle 5, Shear 1.05 Type 2, Spindle 5, Shear 0.26 Type 3, Spindle 4, Shear 1.05 Type 3, Spindle 5, Shear 1.05 Type 2, Spindle 3, Shear 1.05 Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52 Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52

5,145.83 5,097.27 4,298.50 4,267.92 4,196.92 3,860.00 3,830.83 3,700.00 3,680.00 3,652.14

0.057

27

Type 2, Spindle 5, Shear 0.26 Type 3, Spindle 4, Shear 1.05 Type 3, Spindle 5, Shear 1.05 Type 2, Spindle 3, Shear 1.05 Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52 Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24

5,097.27 4,298.50 4,267.92 4,196.92 3,860.00 3,830.83 3,700.00 3,680.00 3,652.14 3,590.00

0.055

28

Type 3, Spindle 4, Shear 1.05 Type 3, Spindle 5, Shear 1.05 Type 2, Spindle 3, Shear 1.05 Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52 Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47

4,298.50 4,267.92 4,196.92 3,860.00 3,830.83 3,700.00 3,680.00 3,652.14 3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00

0.055

29

Type 2, Spindle 3, Shear 1.05 Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52 Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09

4,196.92 3,860.00 3,830.83 3,700.00 3,680.00 3,652.14 3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75

0.052

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

484

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

30

Type 2, Spindle 6, Shear 0.10 Type 2, Spindle 5, Shear 0.52 Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47

3,860.00 3,830.83 3,700.00 3,680.00 3,652.14 3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00

0.086

31

Type 1, Spindle 6, Shear 1.05 Type 3, Spindle 6, Shear 0.05 Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52

3,700.00 3,680.00 3,652.14 3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00

0.066

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

485

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

32

Type 1, Spindle 4, Shear 0.52 Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05

3,652.14 3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67

0.051

33

Type 1, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05

3,590.00 3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00

0.051

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

486

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

34

Type 2, Spindle 4, Shear 1.05 Type 1, Spindle 3, Shear 1.05 Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24

3,377.14 3,342.94 3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86

0.055

35

Type 3, Spindle 3, Shear 2.09 Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24

3,251.03 3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59

0.060

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

487

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

36

Type 3, Spindle 6, Shear 0.26 Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09

3,158.33 3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79

0.053

37

Type 2, Spindle 6, Shear 0.26 Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05

3,027.27 2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67

0.055

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

488

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

38

Type 3, Spindle 5, Shear 2.09 Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24

2,943.08 2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65

0.057

39

Type 1, Spindle 5, Shear 2.09 Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47

2,934.17 2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50

0.050

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

489

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

40

Type 3, Spindle 6, Shear 0.52 Type 2, Spindle 5, Shear 1.05 Type 3, Spindle 6, Shear 10.47 Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24

2,833.33 2,820.77 2,720.00 2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89

0.062

41

Type 1, Spindle 2, Shear 1.05 Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47

2,631.17 2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92

0.063

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

490

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

42

Type 3, Spindle 6, Shear 0.10 Type 3, Spindle 4, Shear 2.09 Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24

2,620.00 2,615.77 2,588.75 2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15

0.051

43

Type 2, Spindle 3, Shear 2.09 Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09

2,588.75 2,425.00 2195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00

0.051

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

491

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

44

Type 2, Spindle 6, Shear 10.47 Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09 Type 2, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 10.47 Type 3, Spindle 6, Shear 5.24

2,425.00 2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00 876.36 810.74 800.00

0.053

45

Type 2, Spindle 5, Shear 2.09 Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09 Type 2, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 10.47 Type 3, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 10.47 Type 1, Spindle 3, Shear 5.24 Type 1, Spindle 2, Shear 5.24

2,195.88 2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00 876.36 810.74 800.00 790.87 748.80 705.04

0.080

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

492

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

46

Type 1, Spindle 6, Shear 2.09 Type 2, Spindle 6, Shear 0.52 Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09 Type 2, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 10.47 Type 3, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 10.47 Type 1, Spindle 3, Shear 5.24 Type 1, Spindle 2, Shear 5.24 Type 2, Spindle 6, Shear 5.24

2,175.00 2,170.00 2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00 876.36 810.74 800.00 790.87 748.80 705.04 535.00

0.052

47

Type 3, Spindle 6, Shear 1.05 Type 2, Spindle 4, Shear 2.09 Type 1, Spindle 4, Shear 1.05 Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09 Type 2, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 10.47 Type 3, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 10.47 Type 1, Spindle 3, Shear 5.24 Type 1, Spindle 2, Shear 5.24 Type 2, Spindle 6, Shear 5.24 Type 1, Spindle 3, Shear 10.47 Type 1, Spindle 2, Shear 10.47

2,041.67 1,981.18 1,970.00 1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00 876.36 810.74 800.00 790.87 748.80 705.04 535.00 437.92 388.69

0.050

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

493

(Table 3 continued) Group Combination Mean viscosity (cP) p-value

48

Type 1, Spindle 5, Shear 5.24 Type 3, Spindle 3, Shear 5.24 Type 3, Spindle 5, Shear 5.24 Type 2, Spindle 5, Shear 5.24 Type 3, Spindle 6, Shear 2.09 Type 1, Spindle 3, Shear 2.09 Type 1, Spindle 2, Shear 2.09 Type 1, Spindle 4, Shear 2.09 Type 3, Spindle 4, Shear 5.24 Type 2, Spindle 6, Shear 1.05 Type 3, Spindle 5, Shear 10.47 Type 2, Spindle 3, Shear 5.24 Type 1, Spindle 5, Shear 10.47 Type 2, Spindle 5, Shear 10.47 Type 2, Spindle 4, Shear 5.24 Type 3, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 5.24 Type 3, Spindle 4, Shear 10.47 Type 2, Spindle 6, Shear 2.09 Type 2, Spindle 3, Shear 10.47 Type 1, Spindle 4, Shear 10.47 Type 3, Spindle 6, Shear 5.24 Type 2, Spindle 4, Shear 10.47 Type 1, Spindle 3, Shear 5.24 Type 1, Spindle 2, Shear 5.24 Type 2, Spindle 6, Shear 5.24 Type 1, Spindle 3, Shear 10.47 Type 1, Spindle 2, Shear 10.47 Type 1, Spindle 6, Shear 10.47

1,782.86 1,716.00 1,707.86 1,680.59 1,616.67 1,546.79 1,496.08 1,490.00 1,480.33 1,416.67 1,345.00 1,337.65 1,289.50 1,283.68 1,257.89 1,066.92 981.15 951.21 950.00 876.36 810.74 800.00 790.87 748.80 705.04 535.00 437.92 388.69 150.00

0.053

Fig. 3. ANOVA Duncan test performed to experimental data that confirm thixotropic behavior is shown in Table 2. In particular, it was found that the viscosities of homemade specimens were higher than those of commercial ones (as shown in Fig. 4). It is noteworthy that the commercial tomato sauce contains additives, thickeners, seasonings, preservatives, etc., in addition to solids naturally present in tomatoes; causing differences in the viscosities of the two types of sauces analyzed in this work. Solids concentration is one of the main factors that can modify the viscosity [18]. Viscosity behavior of homemade tomato sauce is different from commercial sauce; which may be due to viscoelastic properties of tomato products, as they are primarily related to average volumetric diameter and insoluble solids content in tomato paste. The solids content is controlled by the

tomato variety and processing conditions [10, 17]. Furthermore, it has been shown that thermal pre-treatment of tomatoes caused the breaking of lycopene chains (natural polymer found in tomatoes) into smaller chains of isoprene [19]. Consequently, it is concluded that the viscosity without this treatment (e.g. Homemade sauce) must be greater than the viscosity of a tomato-based commercial sauce product. Moreover, the spindle effect over the viscosity-shear rate curves or stress-shear rate curves is shown in Figs. 5-7. In those figures it is shown that the larger varations on homemade and commercial tomato puree viscosity occurred at lower shear rates (lesser than 5 rad/s). The effect of type of sauce (either homemade or commercial), spindle, and shear rate is shown in Table 3, where Duncan statistical analysis was performed for all experimental specimens tested.

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

494

Fig. 3 Thixotropic effect of a typical specimen tested of commercial tomato sauce using spindle number 3 and a shear rate of 0.26 rad/s: Diamond (loading test) and Square (un-loading test).

Fig. 5 Effect of spindle used on the viscosity—shear rate behavior of commercial tomato sauce: Diamond (spindle 3), Square (spindle 4), Triangle (spindle 5), Cross (spindle 6).

Fig. 4 Variation of apparent viscosity of a typical specimen of homemade (Diamond) and commercial (Square) tomato sauce as a function of time at a shear rate of 0.26 rad/s using spindle number 5.

Fig. 6 Effect of spindle used on the viscosity—shear rate behavior of home-made tomato sauce: Diamond (spindle 2), Square (spindle 3), Triangle (spindle 4), Cross (spindle 5), Asterisk (spindle 6).

Shear Rate Effect on the Viscosity of Homemade and Commercial Tomato Sauce

495

Fig. 7 Effect of spindle used on the stress—shear rate behavior of commercial tomato sauce: Diamond (spindle 3), Square (spindle 4), Triangle (spindle 5), Cross (spindle 6).

4. Conclusions

It was showed that the tomato sauce has the characteristics of a thixotropic fluid since the apparent viscosity decreases as time passed. When tomato sauce is at rest, it has a gel-dimensional microstructure. By applying a shear stress, agitation generates the microstructure breakdown in linear chains as time passes, breaking the physical links, thereby causing a decrease in viscosity. The 48 different groups were determined using Duncan statistical test, from nearly 96 possible combinations of type of sauce, spindle and shear rate used to obtain the viscosity of each specimen analyzed.

The results obtained in this study, conducted in the range of shear rates from 0.05 to 10.47 s-1, are similar to those obtained by Barbana and El-Omri [12], although they experienced only over a range of 0 to 1.291 s-1. Augusto et al. [8, 9] demonstrated the thixotropic behavior of tomato juice samples at different shear rates (50 to 500 s-1). Besides time effect, it was found that the apparent viscosity decreased when spindle was changed in ascending order for commercial tomato sauce at shear rates

lower than 2.094 s-1. At higher shear rates, the viscosity was not significantly altered. In addition, homemade sauce viscosity is greater than that of commercial sauce, probably due to the thermal pre-treatment that is performed to tomato-based commercial products, which breaks polymeric chains of lycopene in smaller chains of isoprene [16], and thereby causing a decrease in the viscosity of the commercial product.

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Modelling of Colour Degradation in Tomato Puree (Lycopersicon esculentum L.).” Food and Bioprocess Technology 4 (5): 781-7.

[2] Heuvelink, E. 2005. Tomatoes. Cambridge, MA, USA: CABI Publishing.

[3] Rao, M. A. 1977. “Rheology of Liquid Foods. A Review.” J. texture Stud. 8: 135-68.

[4] Muller, H. G. 1973. “Introducción a la Reología de los Alimentos.” 1a Edición, Editorial Acribia, Zaragoza España.

[5] Rao, M. A. 2005. “Rheological Properties of Fluid Foods.” In: Engineering Properties of Food. Rao, M. A., Rizvi, S. S. H., and Datta, A. K. 3ra Edición, 41-99. Boca Ratón, FL, USA: CRC Press.

[6] Steffe, J. F. 1996. Rheological Methods in Food Process Engineering. 2a Edición, USA: Freeman Press.

[7] Roudot, A. C. 2004. “Reología y Análisis de la Textura de los Alimentos.” 1st Ed., Editorial Acribia, Zaragoza, España.

[8] Augusto, P. E. D., Falguera, V., Cristianini, M., and Ibarz, A. 2010. “Rheological Behavior of Tomato Juice: Steady—State Shear and Time—Dependent Modeling.” Food Bioprocess Technol. ISSN 1935-5130, p. 1-9.

[9] Augusto, P. E. D., Falguera, V., Cristianini, M., and Ibarz, A. 2012. “Rheological Behavior of Tomato Juice: Steady-State Shear and Time-Dependent Modeling.” Food and Bioprocess Technology 5 (5): 1715-23.

[10] Bayod, E., Mansson, P., Innings, F., Bergenstahl, B., and Tomberg, E. 2007. “Low Shear Rheology of Concentrated Tomato Products. Effect of Particle Size and Time.” Food Biophysics 2: 146-57.

[11] Ramos, A. M., and Ibarz, A. 1998. “Thixotropy of Orange Concentrate and Quince Puree.” Journal of Texture Studies 29: 313-24.

[12] Barbana, C., and El-Omri, A. 2012. “Viscometric Behavior of Reconstituted Tomato Concentrate.” Food Bioprocess Technol. 5: 209-15.

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[13] Hayes, W. A., Smith, P. G. Y., and Morris, A. E. J. 1998. “The Production and Quality of Tomato Concentrates.” Critical Reviews in Food Science and Nutrition 38 (7): 537-64.

[14] Moelants, K. R. N., Jolie, R. P., Palmers, S. K. J., Cardinaels, R., Christiaens, S., Van Buggenhout, S., Van Loey, A. M., Moldenaers, P., and Hendrickx, M. 2013. “The Effects of Process-Induced Pectin Changes on the Viscosity of Carrot and Tomato Sera.” Food and Bioprocess Technology 6 (10): 2870-83.

[15] Torbica, A., Belović, M., Mastilović, J., Kevrešan, Ž., Pestorić, M., Škrobot, D., and Dapcević-Hadnadev, T. 2016. “Nutritional, Rheological, and Sensory Evaluation of Tomato Ketchup with Increased Content of Natural Fibres Made from Fresh Tomato Pomace.” Food and Bioproducts Processing 98: 299-309.

[16] Belović, M., Pajić-Lijaković, I., Torbica, A., Mastilović, J., and Pećinar, I. 2016. “The Influence of Concentration and Temperature on the Viscoelastic Properties of Tomato Pomace Dispersions.” Food Hydrocolloids 61: 617-24.

[17] Valencia, C., Sanchez, M. C., Ciruelos, A., Latorre, A., Franco, J. M., and Gallegos, C. 2002. “Linear Viscoelasticity of Tomato Sauce Products: Influence of Previous Tomato Paste Processing.” Eur. Food Res. Technol. 214: 394-9.

[18] Bourne, M. C. 1982. Food Texture and Viscosity. San Diego, California: Academic Press.

[19] Galicia-Cabrera, R. M. 2009. “Extracción de pigmentos carotenoides en jitomate (Lycopersicon esculentum Mill) y su aplicación en sistemas alimentarios modelo.” Tesis Doctoral en Biotecnología, Universidad Autónoma Metropolitana, México D. F., Septiembre.