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Formation and rheological properties of mixed protein-polysaccharide gels (composites) was studied. The composites consisted of whey proteins gelling separately, which were surrounded by polysaccharide gel. The polysaccharide gels were obtained from κ-carrageenan and κ-carrageenan-galactomannan (guar gum and locust bean gum) mixtures. The texture of gels obtained was examined by their compression and bending test. The composite gels obtained from 14% WPI solution and the 1.5% mixture of κ-carrageenan with locust bean gum in a 1:1 ratio exhibited a higher shear stress value at fracture in comparison to WPI gels, but they were less resistant to fracture in the bending test. The texture of gels was highly influenced by pH.
Milk and dairy products are high-value foods; however, consumers suffering from lactose intolerance are not able to enjoy the nutritional benefits of these commodities. There are more and more researches and developments focusing on lowering the lactose content of milk and dairy foods in order to make them available for lactose intolerant people. In this study, we examined the coagulation time, product quality, texture profile properties, and syneresis of yoghurts prepared from lactose-free milk. Significant differences were observed between the control and lactose-free milks with respect to coagulation time and texture profile. The first rupture time, the hardness, and the adhesion force of the lactose-free yoghurt were higher compared to the control product. We observed remarkable difference between the whey leakage of control and lactose free yoghurt samples (21.47% and 14.63%). Results coming from instrumental texture profile analyses showed that the preliminary lactose hydrolysis of milk resulted a firmer texture. It was confirmed by the results of sensory evaluation, and considering the texture and taste, there was significant difference between the control and lactose-free yoghurts.
Sunflower (PSH 569) was used to obtain textured defatted meal. Proximate analysis, water absorption index (WAI), water solubility index (WSI), fat absorption capacities (FAC), foaming capacity (FC), and bulk density (BD) were determined. The objective of the study was the optimization of extrusion conditions for production of textured defatted sunflower meal using response surface methodology (RSM) by evaluating functional properties. It was dried, grinded, and sieved to eliminate hull and fibre. Numerical optimization provided eight solutions with desirability value varying from 0.81 to 0.82. Range of predicted values of FAC (80.96–90.49), WHC (1.95–2.12), WSI (3.22–3.36), WAI (2.84–3.08), bulk density (0.31–0.36), and foaming capacity (14.39–16.30) were used for numerical optimization. Best extrusion conditions were 16.36% feed moisture, 300 r.p.m. screw speed, and 149.40 °C barrel temperature. Textured sunflower defatted meal was prepared using the above optimized conditions.
35 129 131 Tscheuschner, H.-D. (1991) Rheological properties of chocolate masses and cocoa butter dispersions and the texture of chocolate. Food
The aim of the work was to develop a method to evaluate the effect of bread improver dosage on bread crumb texture. Standard breads were prepared to get different crumb structures when bread improver was added to the flour in a concentrate of 0.2%, 0.4% and 0.6%. The additive used in the experiments contains lecithin, ascorbic acid and alpha-amylase. Rheological tests and image analysis were performed to predict the effect of the additive. Hardness, chewiness, gumminess, cohesiveness and springiness were determined by rheological method. The rheological properties neither separately nor combined were able to discriminate the different bread crumb groups. Image processing method was developed to determine the ratio of dark to light area of the images taken of the bread slices. It was concluded that both rheological and visual parameters should be taken into account to characterize bread crumb texture.
Potato wedges were deep, shallow, and par-fried in soybean, sesame, and mustard oils using a laboratory formulated citric acid based antioxidant. The wedges were stored at –18 °C for 10, 20, 30, and 40 days. The quality of the wedges was assessed by subjective method (sensory analysis) and objective method (texture studies). Fuzzy logic was applied as a tool to analyze the linguistic data of subjective evaluation. Objective evaluation was conducted by studies on hardness, shear modulus and shear energy of the wedges. The wedges with highest defuzzified scores (obtained by sensory evaluation) and minimum changes in textural properties (P<0.05) were obtained in par-fried soybean oil (after 40 days storage) and in deep fried sesame and mustard oils (both after 30 days storage). The ranking of fried wedges (in the antioxidant administered oils) based on defuzzified scores after 40 days were: sesame > mustard > soybean (deep fry), mustard > soybean > sesame (shallow fry) and soybean > mustard > sesame (par-fry).
The fat content of Bologna-type turkey sausages was partially replaced with pea fiber or potato starch. Textural properties of full fat turkey sausage were mainly restored in sausages when fat was partially replaced with some levels of pea fiber (0.6, 1.2%) or potato starch (1.9%). Authors observed significant correlation (P<0.01) between instrumentally measured values of hardness and chewiness and sensory ratings of low fat sausages.
The enrichment of bread with wheat bran as a source of dietary fibre seems to be necessary for human health, because bread is the most consumed commodity in many countries. However, wheat bran has some adverse effects on the bread quality during storage. The aim of this study was to produce barbari bread with increased nutritional value and improved texture by the addition of coated wheat bran (0.67 and 1.34% based on flour stearic acid or St1, 2 and beeswax or Bw1, 2). Bread made from uncoated wheat bran was used as control. The least crust to crumb ratio was seen for control and Bw1. Water activity and moisture content results showed that the crumb of Bw1 and control had the better moisture retention during storage. Textural properties of samples showed that there were no significant differences in the hardness of the samples (P>0.05). However, the least increase in hardness during storage was observed for stearic acid coated samples. Other texture profile analysis parameters, such as cohesiveness and springiness, showed that Bw1 and Bw2 samples had no significant changes during storage. Differential scanning calorimetry (DSC) showed the least enthalpy for Bw1 after baking (385.21 J g–1) and during storage (567.62 J g–1). Accordingly, results showed that beeswax, especially at 0.67% (based on flour), is the best shell material for bran coating in order to improve bread texture and shelf life.
Eight descriptive sensory textural attributes of whole date fruit were evaluated by twenty trained panel members and correlated with sixteen physicochemical properties. All sensory parameters, except gumminess, significantly correlated (Ps<0.05) with pectin, crude fibre, and moisture content. In addition, sensory hardness, cohesiveness, elasticity, and resilience correlated significantly with length of whole fruit (P<0.05), sensory adhesiveness with glucose content (P<0.05), sensory chewiness with mass of whole fruit (P<0.05), and sensory gumminess with fructose, glucose, and total sugar content (P<0.10). Sweetness, however, correlated only with moisture content (P<0.05). CA and the biplot (i.e. including all products, their sensory texture and physicochemical attributes) generated through PCA recognized three groups of dates as hard-chewy, soft-(medium-chewy), and soft-(non-adhesive).
The influence of storage time on different quality parameters and in vitro antioxidant activity of peaches cv. Elegant Lady harvested at two ripening stages (immature and commercial mature) and stored under cold and marketing conditions were assessed. Destructive (physical-chemical properties, antioxidant activity, and firmness) and non-destructive parameters (colour and index of absorbance difference, IAD) were assessed.
Storage and ripening stage influenced firmness, colour, and antioxidant activity. Firmness decreased significantly during cold and marketing storage, and skin colour parameters, a* and b*, underwent a deepening of the red hue, while IAD values fully justified differences in colour over storage time and ripening stage. The antioxidant activity increased during storage, although polyphenols and ascorbic acid contents remained constant, and was higher in commercial mature fruit than immature peaches, that revealed a ratio of total sugars/total acids more equilibrated.
