ABSTRACT
Increasing trends of overweight and obesity prevalence have prompted food producers to develop products that can enhance satiety signals. The role of short-chain fatty acids as satiety-inducing triggers seems to be of interest in this regard. The objective of this research was to investigate the impact of two process variables, namely, incubation temperature and inoculation ratio of starter bacteria, on propionic acid production in the fermented dairy beverages containing Propionibacterium immediately after fermentation and during cold storage. Fermented dairy beverage [FDB] samples were prepared using mixed cultures of Lactobacillus acidophilus and Propionibacterium freudenreichii ssp. shermanii at a ratio of 1:2, 1:4 and 1:8, repectively, at incubation temperatures of 30, 35 and 40°C, until the pH reached 4.0 +/- 0.1. Propionic, lactic and acetic acid contents of the samples were measured immediately after fermentation using HPLC. The FBD samples were refrigerated for 28 days and the concentrations of the acids in the samples with the highest propionic acid content were measured. Sensory evaluation of the samples produced was made by 11 trained panelists using the hedonic scale. The maximum propionic acid content [w/w%] was observed in a mixed culture of L. acidophilus and P. freudenreichii ssp. shermanii at a ratio of 1:4 and an incubation temperature of 30 °C. It increased from 0.75 at day 0 to 1.2 at day 28 during storage at 4°C. The incubation temperature had a statistically significant inverse effect [P<0.05] on the propionic acid production in the fermented dairy beverages
ABSTRACT
Chocolate is very popular among consumers of all ages. However, its consumption is limited for the obese and diabetic people due to its high energy and sucrose contents. Replacing sucrose by low digestible carbohydrates [LDC[s] will result in lowering its energy content and glycemic index, as well as in preventing tooth decay. The objective of the present study was to investigate the effects of replacing sucrose with 2 sugar substitutes, namely, D-tagatose and inulin, on the physical, chemical, rheological and sensory properties of dark chocolate. Inulin, a dietary fiber, and D-tagatose, a natural keto-hexose with a degree of sweetness similar to that of sucrose, were used as sucrose substitutes in dark chocolate formulas. The inulin:tagatose ratios in the mixtures were 100:0, 75:25, 50:50, 25:75, and 0:100. The physical, chemical, rheological, and sensory properties of chocolate samples prepared with the mixtures were determined. With a reduction in the inulin content and an increase in the tagatose content, the moisture contents of the chocolate samples decreased, while their a[w] increased. Increased D-tagatose resulted in increased hardness of the samples, the sample with 100% being the hardest, comparable to the control [sucrose] value. With regard to color indices, the least amounts of L*,a*,b*,c* and hue° were observed in chocolate samples with 100% inulin. Increasing D-tagatose led to increases in the color indices. The data also showed that reductions in inulin resulted in decreases in apparent and plastic viscosity and increases in ?0 and ?1. Thus, the lowest real and linear yield stresses were found to be in the sample with 100% inulin. The least apparent viscosity and the lowest plastic viscosity were observed in samples with 25% inulin-75% tagatose and 100% tagatose, respectively, with no significant difference with the control value. Overall acceptability of the chocolate samples increased with increasing the D-tagatose level. It can be concluded that in chocolate formula samples an inulin-tagatose ratio of 25%-75% and 100% tagatose are the best sucrose substitutes. As inulin is a dietetic fiber and tagatose and inulin have prebiotic properties, chocolate samples prepared using them are also desirable from a nutritional point of view and can be considered as functional foods
ABSTRACT
The aim of this study was to produce Taftoon bread from wheat flour fortified with defatted soy flour and assess its chemical and organoleptic properties, as well as its growth-promoting effect in rats. Samples of wheat flour with extraction rates of 82-84%, fortified with 3, 7 or 12% defatted soy flour were used to bake Taftoon bread. Bread produced from these blends was compared with regular Taftoon bread and tested for chemical and organoleptic characteristics. Forty Sprague Dawley rats were randomly divide into groups to be fed, for 30 days, on one of the three defatted soy flour fortified bread blends, a group fed on ordinary Taftoon bread serving as controls. Chemical, biological, and organoleptic assessments were made on the bread samples. The blending of wheat flour with defatted soy flour at different levels altered the organoleptic properties of breads. Addition of defatted soy flour significantly increased the protein and ash contents of the breads [P< 0.05]. Organoleptic tests with 213 untrained panelists indicated that the best formulation is one containing 3 or 7% defatted soy flour. Rats fed on the control diet had the lowest weight gain and their feed efficiency ratio was significantly different [P < 0.05] from that of the group fed the 7% defatted soy flour formula. Based on chemical, organoleptic, and biological evaluations, it is concluded that the best Taftoon bread formulation is one containing wheat flour fortified with 3-7% defatted soy flour