Effect of honeydew honey addition on the water activity and water holding capacity of kefir in the context of its sensory acceptability.

The aim of the research was to check how the addition of honeydew honey and various compositions of starter cultures affects the water holding capacity, water activity, color, syneresis and consistency of the obtained kefir in the context of its sensory acceptability. In this research, 2.5% and 5% (w/w) honeydew honey was added to the samples of model kefir (K) and commercial kefir (K13). Kefirs differed by the type of used starter cultures and conditions of production. The addition of honeydew honey to kefir resulted in increased water holding capacity and a reduction in water activity. Honeydew honey kefir was characterized by the following flavor: astringent, fruity, pungent and waxy. As the honey content increased, the taste and waxy flavor became sweeter. In the sensory assessment, the attributes of texture and mouthfeel, creaminess, density and firmness, do not change because of the honey amount or storage time of the samples. The use of different starter cultures in kefir production with the addition of honeydew honey impacted texture parameters, resulting in up to a 4.8-fold increased viscosity index.

Oxysterols in stored powders as potential health hazards.

Cholesterol oxidation products (COPs) have greater biological activity than cholesterol itself. Oxysterols reduce the nutritional value of foods and exhibit a wide range of biological activity, including pro-oxidant, carcinogenic, and cytotoxic properties. The most commonly detected oxysterols in foods are 7α-HC, 7ß-HC, a product of their dehydrogenation 7-KC and α-CE, ß-CE. The main dietary sources of oxysterols are eggs and egg-derived products, thermally processed milk and milk-based products, fried meat. This study aimed to measure the amount of cholesterol oxidation products in milk powder, egg powder and milk-egg powder during 24 months of storage. The changes in the selected oxysterols (determined by gas chromatography) were recorded. In milk powder, after the production process, the amount of cholesterol was 0.2 g 100 g-1 fat and in egg powder it was 3.4 g 100 g-1. After 6 months of storage, the dominant oxysterol in milk and egg powder was 7α-HC and in milk-egg powder it was 7-KC. After the storage period, oxysterols in powdered milk reached 1.81% of total cholesterol.  The most stable cholesterol was in the milk-egg mixture and its oxidation was the slowest. This study showed the presence of COPs in milk powder, egg powder and milk-egg powder and the effect of storage on cholesterol oxidation.

Color Stability of Fermented Mare's Milk and a Fermented Beverage from Cow's Milk Adapted to Mare's Milk Composition.

Color is important for the consumer when making a purchase decision. Mare's milk and, thus, fermented mare's milk is little known to consumers. Thus, it is worth presenting research showing the extent of color change during the production and storage of mare's milk. Herein, we examined the range of color changes in mare's milk and cow's milks adapted to mare's milk composition. These samples were further fermented and stored for 3 weeks at 5 ± 1 °C. Starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used for fermentation. Mare's milk reached the required pH of 4.5 during fermentation faster (255 min) than cow's milk (300 min). After fermentation, mare's milk compared to cow's milk and adapted cow's milk had lower titratable acidity (0.75%) and firmness (145. 6 |(g∙s)|). The water holding capacity (95.6%) and number of Lactobacillus (7.71 log CFU/mL) and Streptocococcus (7.20 log CFU/mL) in mare's and other's milks were the same. Mare's milk was furthest from the ideal white (WI) color, with its chrome (C*) being 1.5-times larger than cow's milk. However, fermented mare's milk was darker than the fermented adapted milk and cow's milk by 36% and 58%, respectively. Storage caused a decrease in the WI, C*, and yellowness index (YI). The fermented mare's milk color stability during production and storage was less than that of fermented cow's milk. After 3 weeks storage, it was observed that the titratable acidity increased to 1.05%, and the pH decreased to 4.3 in fermented mare's milk. The water holding capacity decreased but was still higher compared to fermented cow's milk.

APPLICATION OF OAT, WHEAT AND RYE BRAN TO MODIFY NUTRITIONAL PROPERTIES, PHYSICAL AND SENSORY CHARACTERISTICS OF EXTRUDED CORN SNACKS.

BACKGROUND: Cereal products constitute the basis of the diet pyramid. While the consumption of such products as bread decreases, the group of food which popularity increase is cereal snacks. Unfortunately, the dietary value of this group of foodstuffs is limited. Thus, different types of cereal bran may be added to the produced snacks to enhance their nutritive value. However, an addition of bran may have an adverse effect on quality attributes of products. METHODS: Corn grits enriched with 20 and 40% oat, wheat and rye bran was extruded. Basic parameters determining the nutritive value, physical characteristics and sensory attributes of the six produced types of extrudates were measured and compared. Moreover, the effect of additives applied on viscosity of aqueous suspensions of the raw materials and extrudates under controlled conditions was measured using RVA. RESULTS: The dietary value of snacks containing bran depends on the type and quantitative shares of the additives. The content of dietary fibre in produced extrudates ranged from 6.5 to 15.8%, including soluble dietary fibre at 2.1 to 3.7%. With an increase of bran content in extrudates, their expansion decreased, density increased and the colour of extrudates changed (reduced brightness, increased a*, decreased b*). In sensory evaluation the highest acceptability was given to extrudates with a 20% addition of oat bran, while the lowest was given for those with 40% wheat bran. Based on PCA results positive correlations were found between overall desirability and crispiness, porosity, taste, colour and expansion. Negative correlations between desirability and hardness and density of extrudates were observed. The additives and their level also had an effect on changes in viscosity of aqueous suspensions measured using RVA. However, no correlation was found between quality features of extrudates and values of attributes measured in the analysis of viscosity. CONCLUSIONS: In the production of corn extruded snacks an addition of oat, wheat and rye bran may be applied up to 20%. Such products have adequate sensory and dietary quality. The Critical Paste Test (Whalen et al., 1996) is not applicable in the evaluation of suitability of the corn raw material with an addition of oat, wheat and rye bran to produce extrudates.