Amal Bakr Shori

Antioxidant activity and viability of lactic acid bacteria in soybean-yogurt made from cow and camel milk

Abstract In the present study soybean (Glycine max L.) was included in cow and camel milk during fermentation. The resulting soybean-yogurt was evaluated with respect to the changes of post-acidification, viable cell counts (VCC) of Lactobacillus spp. and Streptococcus thermophilus, total phenolic content (TPC) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) inhibition assay during 21 days of refrigerated storage. The presence of soybean in fresh cow- and camel-milk yogurts did not affect pH reduction compared to respective plain-yogurt. However, soybean–camel milk yogurt showed significant reduction in pH (4.05 ± 0.06) compared to plain-yogurt 4.35 ± 0.02 on day 7 of storage. Titratable acidity (TA) increased in soybean–cow milk yogurt (p < 0.05) but not in soybean–camel milk yogurt as compared with respective plain-yogurt during period of storage. The presence of soybean in fresh yogurt showed increased (p < 0.05) in Lactobacillus spp. VCC by 10% in cow milk-yogurt and 30% in camel milk-yogurt compared to respective plain-yogurts. On the other hand, VCC of S. thermophilus was higher (p < 0.05) in the presence of soybean in cow milk yogurt than in camel milk yogurt. Soybean–camel milk yogurt had 2-folds higher TPC on day 0 and 7 (149.59 ± 1.8 and 111.44 ± 2.8 μgGAE/ml respectively) than plain-camel milk yogurt (60.04 ± 0.01 and 55.22 ± 0.01 μgGAE/ml respectively). The highest value of TPC in soybean–cow milk-yogurt was showed on day 21 of storage (43.17 ± 1.2 μgGAE/ml). The antioxidant activity increased (p < 0.05) in the presence of soybean in both cow and camel milk yogurts compared to respective controls. The highest antioxidant activity was shown on day 0 for soybean–cow milk yogurt (61.76 ± 2.2%) and day 7 for soybean–camel milk yogurt (53.16 ± 0.1%). In conclusion, the addition of soybean in both cow- and camel-milk yogurts enhanced the viability of LAB and antioxidant activity during refrigerated storage.

Screening of antidiabetic and antioxidant activities of medicinal plants

Diabetes is a common metabolic disorder characterized by abnormally increased plasma glucose levels. Postprandial hyperglycemia plays an essential role in development of type-2 diabetes. Inhibitors of carbohydrate-hydrolyzing enzymes (such as α-glucosidase and α-amylase) offer an effective strategy to regulate/prevent hyperglycemia by controlling starch breakdown. Natural α-amylase and α-glucosidase inhibitors, as well as antioxidants from plant-based sources, offer a source of dietary ingredients that affect human physiological function in order to treat diabetes. Several research studies have investigated the effectiveness of plant-based inhibitors of α-amylase and α-glucosidase, as well as their antioxidant activity. The aim of this review is to summarize the antidiabetic and antioxidant properties of several medicinal plants around the world. Half inhibitory concentration (IC50, for enzyme suppression) and half effective concentration (EC50, for antioxidant activity) values of less than 500 μg/mL were defined as the most potent plant-based inhibitors (in vitro) and are expected to provide interesting candidates for herbal treatment of diabetes, as foods, supplements, or refined drugs.

Viability of lactic acid bacteria and sensory evaluation in Cinnamomum verum and Allium sativum-bio-yogurts made from camel and cow milk

Abstract The present study investigate the effect of herbal water extract prepared from Allium sativum and Cinnamomum verum on the viability of lactic acid bacteria (Lactobacillus spp and Streptococcus thermophilus) in cow- and camel-milk yogurts during 21 day refrigerated storage. The organoleptic properties of fresh-yogurts were evaluated. Lactobacillus spp count for fresh cow milk-yogurts (0 day) in both present and absent of C. verum and A. sativum was ranged from 1.4 × 06 to 2.1 × 106 cfu/mL. These values were not significantly changed throughout the 21 days of refrigerated storage. Lactobacillus spp count in fresh plain camel milk- yogurt was 13.2 × 106 cfu/mL whereas fresh C. verum- and A. sativum-camel milk- yogurts had higher Lactobacillus spp counts (19.2 × 106 and 26.9 × 106 cfu/mL respectively; p < 0.05). However, refrigerated storage to 21 days resulted in linear decrease in Lactobacillus spp counts. Furthermore, S. thermophilus counts in fresh cow- and camel- milk yogurts in either absent or present of C. verum or A. sativum ranged from 2.4 to 3.6 × 108 cfu/mL and these values increased by day 14 of storage. In organoleptic properties of yogurts no differences were observed in sourness, bitterness, and overall preference scores between the two groups of yogurts. The present of A. sativum in cow milk-yogurt reduced the aroma score to (2.3 ± 0.7, p < 0.05) compared to camel milk-yogurt (5.5 ± 1.0).

Survival of Bifidobacterium bifidum in cow- and camel-milk yogurts enriched with Cinnamomum verum and Allium sativum

Abstract The effects of Allium sativum and Cinnamomum verum water extracts on the survival of Bifidobacterium bifidum during 21 days of refrigerated storage and after simulated gastrointestinal digestion (SGD) were investigated. Two types of yogurt (cow- and camel-milk yogurts) were prepared in the presence of A. sativum or C. verum. The viable cell counts (VCC) of B. bifidum in fresh A. sativum- or C. verum-cow milk yogurt (1 day) were higher (8.1 × 109 cfu/ml and 6.6 × 109 cfu/ml, respectively; p < 0.05) than plain-yogurt (1.9 × 109 cfu/ml). In contrast, B. bifidum VCC in fresh plain-camel milk yogurt was 1.99 × 109 cfu/ml whereas the presence of A. sativum or C. verum in yogurt increased (p < 0.05) VCC to 19.61 × 109 cfu/ml and 25.55 × 109 cfu/ml, respectively. The VCC of B. bifidum in both herbal-yogurts decreased (p < 0.05) during refrigerated storage for both types of yogurt. The VCC of B. bifidum was ∼1.3 × 109 cfu/ml in all fresh cow milk yogurts after 1 h gastric digestion. Intestinal digestion (1 h) increased VCC of B. bifidum in all fresh yogurts but not in 7 day old yogurts (plain- and A. sativum-yogurts). However, prolonged digestion to another 1 h in intestine reduced (p < 0.05) VCC of B. bifidum in all fresh and storage yogurts. In contrast, all fresh camel milk yogurts showed VCC of B. bifidum ⩽1 × 109 cfu/ml after SGD. Seven day old A. sativum – camel milk yogurt showed the lowest survival of B. bifidum after gastric digestion compared to plain- and C. verum-yogurt. The VCC reduced (p < 0.05) in all camel milk-yogurts after 2 h intestinal digestion.

Antioxidant properties of dairy products fortified with natural additives: A review

Abstract Antioxidant is a molecule that inhibits the oxidation of other molecules caused by free radicals. Antioxidant activity of a dairy food is important both for the shelf life of the product as well as for protection from oxidative damage in the human body. The objective of this work was to demonstrate the effects of natural antioxidants (plant-based sources) against synthetic antioxidants in dairy food.

Comparison of the effect of green, white and black tea on Streptococcus thermophilus and Lactobacillus spp. in yogurt during refrigerated storage

Abstract This study investigated the effects of green, white and black tea (Camellia sinensis) on lactic acid production and the viability of Streptococcus thermophilus and Lactobacillus spp. in yogurt during 3 weeks of refrigerated storage. Three types of tea water extracts were added into a milk-starter culture mixture and incubated at 42 °C until the pH was reduced to 4.5. All yogurts were then refrigerated (4 °C) for up to 21 days and samples were analyzed for pH, titratable acid and viable counts of yogurt bacteria. Higher pH values (p < 0.05) were shown in tea yogurts than plain yogurt (PY). Green tea yogurt (GTY) showed the highest pH followed by black tea yogurt (BTY) and white tea yogurt (WTY), respectively for the overall storage period. However, higher acid production was observed in all tea yogurts (0.78–0.99% lactic acid equivalent; LAE) than plain yogurt (0.70–0.91% LAE). Inclusion of three types of tea extracts did not affect significantly (p > 0.05) the viability of Lactobacillus spp. and S. thermophilus compared to PY during storage. All the three types of tea yogurt maintained a high level of S. thermophilus and Lactobacilllus spp. counts through refrigerated storage and this can ensure health benefits to be delivered to consumers on daily consumption.

Sensory Evaluation of Allium sativum - Cheddar Cheese in the Presence and Absence of Fish Collagen during Ripening and Refrigerated Storage

The production of Allium sativum (AS) cheddar cheese in the presence and absence of fish collagen (FC) compared to plain cheese with/without FC was conducted to determine sensory evaluations during 0, 14, 30, and 60 days of ripening. The evaluation system consists of seven parts; outer appearance, colour, texture, consistency of body, consistency of colour, flavour and aroma. Ripened cheeses were assessed by a sensory panels based on a 10-point system. The present results demonstrated that outer appearance of AS cheese in presence of FC showed the lowest score (2.8 ± 0.09) after 8 weeks of ripening. The color criteria of all fresh cheese samples reduced significantly (p<0.05) at the end of ripening period. The highest flavor score of cheese samples was shown at week 2 of ripening for all cheese samples except of AS-cheese. AS-cheese in the presence and absence of FC registered lower aroma score than their respective control during the period of ripening. In conclusion, AS- and AS+FC-cheeses can be consumed within 2 to 4 weeks of storage for the best organoleptic properties.

The Influence of Allium sativum or Cinnamomum verum on Cow- and Camel-Milk Yogurts: Proteolytic and Angiotensin-I Converting Enzyme-Inhibitory Activities

Yogurt is a nutritious dairy product, has established probiotics effects and may even be therapeutic for certain health conditions. Proteolytic activity of starter cultures during milk fermentation can be generating peptides with angiotensin-I converting enzyme (ACE-I; EC. 3.4.15.1) inhibitory activity. Effects of presence of Allium sativum or Cinnamomum verum on these peptides in yogurt were investigated. Two types of milk (cow and camel) were incubated (41°C) with starter culture in the presence of A. sativum or C. verum water extract until pH of yogurt was reduced to 4.5. The resulting herbal-yogurts were evaluated with respect to changes of in vitro ACE-I inhibitory activity and proteolytic activity during 21 days of storage. In the present study, the extent of proteolysis was higher (p<0.05) in presence of A. sativum than presence of C. verum during storage with cow milk yogurt being more susceptible than camel-milk yogurt. The presence of A. sativum or C. verum increased ACE-I inhibitory activity more in cow-than camel-milk yogurt during storage. All herbal-yogurts showed the highest inhibitory activity of ACE-I (40%- 70%) on day 7 of storage. Prolonged storage of both types of yogurt to more two weeks decreased ACE-I inhibition activity (37% - 50%; p<0.05). In conclusion, A. sativum and C. verum can enhance yogurt functional properties with potential therapeutic values for hypertension.

Tamarindus indica seeds improve carbohydrate and lipid metabolism: An in vivo study

Background The tamarind seeds have a lot of nutrients that may be used to control cholesterol or glucose levels. Objective(s) The effects of tamarind seeds (T) on lipid and carbohydrate metabolism in rats were studied. Rats were offered basal diet (BD) with T (2%, 4% or 8%) or without T. Materials and methods Feeding and growth performance in rats were measured and samples of liver and blood were analyzed for glycogen content and levels of cholesterol and glucose respectively. Results The inclusion of T in the diet influences the feeding and growth performance in rats. The serum cholesterol level was reduced (p < 0.05) in Sprague Dawley (SD) rats fed on basal diet (BD) containing 4% and 8% T (0.24 ± 0.14 g/l and 0.31 ± 0.06 g/l respectively) compared to control (0.79 ± 0.04 g/l). The serum glucose levels in the spontaneous hypertensive rats (SHR) was lower (50.74 ± 2.50 mg/dl; p < 0.05) than control (93.52 ± 10.83 mg/dl) at 4% T. Incorporation of increasing doses of T resulted in linear increase of glycogen storage in livers of SD rats fed on BD and high sucrose diet. Conclusion Tamarind seeds can lower blood glucose and serum cholesterol and enhance storage of glycogen in rats.