Kefir Properties Prepared with Goat Milk and Black Rice (Oryza sativa L.) Extract and its Influence on the Improvement of Pancreatic beta-Cells in Diabetic Rats

Abstract

This study were to evaluate the properties of kefir prepared with a combination of goat milk and black rice extract and its influence on the improvement of β-cells in streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats. Kefir was divided into four groups using the following materials: goat milk (GM), goat milk+inulin (GM+IN), goat milk+black rice extract (1:1)(GM+BRE), and goat milk+black rice extract+ inulin (GM+BRE+IN). After fermentation, all kefir were stored at 4°C for 1 and 7 d, and then were analyzed for microbial, chemical properties and antioxidant activity. Furthermore, three kinds doses of kefir combination from goat milk and black rice extract (GM+BRE) were administered to rats. Thirty male rats 8-12 weeks old were divided into 6 groups: 1) negative control (normal rats); 2) positive control (untreated diabetic rats); 3) diabetic rats fed kefir (1.0 ml); 4) diabetic rats fed kefir (2.0 ml); 5) diabetic rats fed kefir (4.0 ml), and 6) diabetic rats received glibenclamide. After 28 d experiment, the rats were sacrificed for sampling pancreatic tissues. Subtitution of goat milk with black rice extract in kefir fermentation could decrease their pH and increase in radical-scavenging activity. Inulin addition able to increase (p<0.05) in radical-scavenging activity of kefir. Alcohol and total phenolic contents of kefir increased (p<0.05) after 7 d of storage, while the pH decreased. To improve insulin-producing pancreatic β-cells in diabetic rats, it was required at least 2.0 ml dose of kefir combination from goat milk and black rice extract to achieve similar effect to glibenclamide as antidiabetic agent.

Kefir and Its Biological Activities

“…The study showed that water kefir scavenged the DPPH free radical from 9.88% to 63.17%, and inhibited the ascorbate oxidation by 6.08-25.57%, demonstrating its potential as an antioxidant agent. A study by Nurliyani et al [139] investigated the properties of kefir fermented with a combination of black rice extract and goat milk and its effects on streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats. The study demonstrated the antioxidant activity of kefir prepared from the combination of black rice extract and goat milk was higher compared to goat milk kefir only.…”

The Many Faces of Kefir Fermented Dairy Products: Quality Characteristics, Flavour Chemistry, Nutritional Value, Health Benefits, and Safety

“…Ebner et al determined 257 peptide sequences from bovine milk kefir, of which the three peptide sequences VYPFPGPIPN, ARHPHPHLSFM and YQEPVLGPVRGPFPIIV exhibited an antioxidant effect [72]. Kefiran was found to possess a beneficial antioxidant effect against reactive oxygen species [117].…”

“…Kefir has demonstrated promising effects in alleviating obesity and associated metabolic dysfunction [118]. Administration of kefir prepared using goat milk and black rice extract showed a similar effect to that of glibenclamide as an anti-diabetic agent [117]. Additionally, feeding of diabetic rats with kefir made from goat milk and soy milk demonstrated an anti-diabetic action as evidenced by a decrease in plasma glucose level concurrent with an increase in glutathione peroxidase (GPx) activity and improved insulin release [119].…”

The Effect of Incorporating Ginger Extract (Zingiber officinale) to Cow Milk Kefir: An Analysis of Antioxidant and Microbiological and Physicochemical Characteristics

“…The kefir making followed the existing method (Nurliyani et al, 2015) with a slight modification. The fresh cow milk was pasteurized (72 o C; 15 seconds), incorporated with ginger extract according to the treatments, then inoculated with kefir grain (10%) at room temperature, and incubated for 24h.…”