Texture profile

The textural characterisation of the jellies was made by using the empirical technique of Texture-Profile Analysis (TPA) that allows the evaluation of the following parameters fracturability, hardness, cohesiveness, adhesiveness, springiness, gumminess and chewiness. 

Texture profile analysis is an empirical technique of double-penetration that simulates two bites of the jaw action. Data obtained from the Force-time plots enable the evaluation of seven texture parameters (Figure 1). 

The data from sensory evaluation and texture profile analysis of the jellies made with amidated pectin and sunflower pectin were subjected to Principal component analysis (PC) using the statistical software based on Jacobi method (Univac, 1973). The results of PC analysis are shown in figure 7. The plane of two principal components (F1,F2) explain 89,75 % of the variance contained in the original data. The attributes related with textural evaluation are highly correlated with the first principal component (Had.=0.95, Spr.=0.97, Che.=0.98, Gum.=0.95, Coe=0.98, HS=0.82 and SP=-0.93). As it could be expected, spreadability increases along the negative side of the axis unlike other textural parameters. 

In the study by Thompson, et al. (11), the ml of gel released per 100 g emulsion for the reference emuTsion without soy, with soy isolate (SIF), soy concentrate (SCF) or soy flour (SF) was 6.07, 5.83, 5.49 and 3.08, respectively, when the hydration ratios were 1 4 (flourrwater) for SIF, 1 3 for SCF and 1 2 for SF. The ml gel released per 100 g emulsion containing 10, 15, 20, and 25% soy protein was 6.70, 5.01, 3.94 and 3.57, respectively. When soy protein concentrate was incorporated into an emulsion at the 3.5% level, the processing yields, textural profile and sensory textural attributes of frankfurters were not different among the products with and without added soy concentrate (13). An objective measure of compression and shear modulus indicated that soy protein concentrate incorporated into frankfurters at the 3.5% level had no effect on batter strength or texture ( M). The addition of a cottonseed protein to frankfurters to replace 5, 10 or 15% of the meat resulted in higher pH, less cured color, less firmness of skin, softer texture and reduced desirability as judged by a sensory panel (J5J. 

Boune, M. C., and Comstock, S. H. (1981). Effect of degree of compression on texture profile parameters. J. Texture Stud. 12, 201-216. 

Paraskevopoulou, A., and Kiosseoglou, V. (1997). Texture profile analysis of heat-formed gels and cakes prepared with low cholesterol egg yoUc concentrates. /. Food Sci. 62, 208-211. 

Pons, M., and Fiszman, S. M. (1996). Instrumental texture profile analysis with particular reference to gelled systems. /. Texture Stud. 27,597-624. 

For mashed potato texture, profile analysis (TPA) and cone penetration tests are performed with a TA HDi Texture Analyser (Stable Micro Systems Ltd, Godaiming, UK). During the tests, the mashed potatoes are kept at 55° C by means of a temperature-controlled Peltier cabinet (XT/PC) coupled to a separate heat exchanger and PID control unit. For the cone penetration tests, a spreadability rig is used, consisting of a 45° conical perspex probe (P/45°C) that penetrates a conical sample holder containing 7 0.1 g of mashed potatoes (Alvarez et al., 2005 Canet et al., 2005b Fernandez et al, 2006). 

Thybo, A. K., Martens, M. (1998). Development of a sensory texture profile of cooked potatoes by multivariate data analysis. Journal of Texture Studies, 29,453 68. 

A detailed method to perform texture profile analysis (TPA) on raw and cooked potatoes has been described by Kaur et al. (2007). The raw or cooked cylindrical pieces are prepared as described... 

Figure 9.2 A typical texture profile analysis force-time curve for raw potato. (Source Singh et al., 2008).

Table 9.2 Texture profile analysis parameters of raw potatoes of different cultivars... 

Gels for quantitating gel characteristics were prepared In screw capped centrifuge tubes (22 X 100 mm) by heating at 100 C for 15 min C14, l, l, ). Gel strength was determined by a penetration technique using the Instron fitted with a disk probe (6.0 ran diameter) (15.16). Instrumental texture profile analysis on gel sections (1.5 X 1,0 cm) was done on an Instron fitted with a... 

Texture profile analyses on Instron as described by Schmidt et al. (25.)-... 

ISO 4287, 1997, Corl, 1998. Geometrical product specification - Surface texture Profile method - Terms, definitions and surface texture parameters. 

H2.1 General Compressive Measurements H2.2 Textural Measurements with Special Fixtures H2.3 Texture Profile Analysis... 

Figure H2.3.1 A generalized texture profile analysis curve from the Instron Universal Testing Machine. A1, area 1 A2, area 2 A3, area 3. The dotted lines indicate the times at which hardness is measured. See text for further discussion. Reprinted from Pons and Fiszman (1996) with permission from Food and Nutrition Press.

Table H2.3.1 Parameters and Units of Instrumental Texture Profile Analysis"...

Bourne, M.C. 1968. Texture profile of ripening pears../. Food Sci. 33 223-226. 

Breene, W.M. 1975. Application of texture profile analysis to instrumental food texture evaluation. J. Texture Stud. 6 53-82. 

TMCS trimethylchlorosilane imidazole TMG tetramethylguanidine TMP 1,1,3,3-tetramethoxypropane TMS trimethylsilyl TNBS trinitrobenzenesulfonic acid TOCSY total correlation spectroscopy TPA texture profile analysis TPCK Af-tosyl-L-phenylalanine chloromethyl ketone... 

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