Processed soymilk effectively ameliorates blood pressure elevation in spontaneously hypertensive rats

Fermented camel milk influenced by soy extract: Apparent viscosity, viscoelastic properties, thixotropic behavior, and biological activities

During fermentation, camel milk forms a fragile, acid-induced gel, which is less stable compared with the gel formed by bovine milk. In this study, camel milk was supplemented with different levels of soy extract, and the obtained blends were fermented with 2 different starter culture strains (a high acidic culture and a low acidic culture). The camel milk-soy extract yogurt treatments were evaluated for pH value, acidity, total phenolic compounds, antioxidant capacities, degree of hydrolysis, α-amylase and α-glucosidase inhibition, angiotensin-converting enzyme inhibition, antiproliferative activities, and rheological properties after 1 and 21 d of storage at 4°C. The results revealed that some of the investigated parameters were significantly affected by the starter culture strain and storage period. For instance, the effect of starter cultures was evident for the degree of hydrolysis, antioxidant capacities, proliferation inhibition, and rheological properties because these treatments led to different responses. Furthermore, the characteristics of camel milk-soy extract yogurt were also influenced by the supplementation level of soy extract, particularly after 21 d of storage. This study could provide valuable knowledge to the dairy industry because it highlighted the characteristics of camel milk-soy yogurt prepared with 2 different starter culture strains.

Hypotensive peptides derived from plant proteins

Hypertension is a risk factor for arteriosclerosis development and is recognized as a silent killer. Certain processed food materials, digested by protease or through the use of fermentation, have shown exertion of hypotensive effects in human clinical or animal studies, and hypotensive peptides were isolated from them. This review discusses the hypotensive peptides derived from plant proteins, such as grain, soy, vegetables, and seaweeds, and their hypotensive mechanisms. Although angiotensin I-converting enzyme (ACE) inhibition is often noted as one of the mechanisms that may exert antihypertensive effects, ACE inhibitory activity measured by in vitro studies is not associated with the actual hypotensive effect. Thus, this review only highlights the peptide hypotensive effect determined by in vivo studies. This review also discusses the tendency of the amino acid sequence of ACE-inhibitory hypotensive peptides and the possible additional effects of hypotensive peptides independent of ACE inhibition.

Comparative Study of Angiotensin I-Converting Enzyme (ACE) Inhibition of Soy Foods as Affected by Processing Methods and Protein Isolation

Angiotensin converting enzyme (ACE) converts angiotensin I into the vasoconstrictor angiotensin II and eventually elevates blood pressure. High blood pressure is a major risk factor for heart disease and stroke. Studies show peptides present anti-hypertensive activity by ACE inhibition. During food processing and digestion, food proteins may be hydrolyzed and release peptides. Our objective was to determine and compare the ACE inhibitory potential of fermented and non-fermented soy foods and isolated 7S and 11S protein fractions. Soy foods (e.g., soybean, natto, tempeh, yogurt, soymilk, tofu, soy-sprouts) and isolated proteins were in vitro digested prior to the determination of ACE inhibitory activity. Peptide molecular weight distribution in digested samples was analyzed and correlated with ACE inhibitory capacity. Raw and cooked soymilk showed the highest ACE inhibitory potential. Bacteria-fermented soy foods had higher ACE inhibitory activity than fungus-fermented soy food, and 3 day germinated sprouts had higher ACE inhibition than those germinated for 5 and 7 days. The 11S hydrolysates showed higher ACE inhibitory capacity than 7S. Peptides of 1–4.5 kDa showed a higher contribution to reducing IC50. This study provides evidence that soy foods and isolated 7S and 11S proteins may be used as functional foods or ingredients to prevent or control hypertension.

Fermented rice bran supplementation mitigates metabolic syndrome in stroke-prone spontaneously hypertensive rats

BACKGROUND

Previous study shown that enzyme treated-rice bran effectively improved hypertension and glucose intolerance in stroke-prone spontaneously hypertensive rat (SHRSP). However, dual fermentation of rice bran's efficacy against metabolic syndrome in SHRSP is still unknown.

METHODS

Fermented rice bran (FRB) was prepared by dual fermentation of rice bran using fungi and lactic acid bacteria. The effect of FRB on metabolic syndrome in stroke-prone spontaneously hypertensive rats (SHRSP) was investigated by single and chronic supplementation.

RESULTS

Dual fermentation of rice bran enriches the functional value of rice bran. Single-dose oral administration of FRB (2 g/kg body weight) reduced systolic blood pressure; however, chronic supplementation with 5 % FRB (4 weeks) significantly reduced both systolic and diastolic blood pressure. FRB supplementation improved leptin impairment and increased serum adiponectin levels and angiotensin-converting enzyme inhibitory activity. Furthermore, FRB supplementation improved glucose tolerance and insulin sensitivity as well as serum insulin levels. Lipid profiles were also improved by the regulation of 5' adenosine monophosphate-activated protein kinase activation. Moreover, supplementation with FRB reduced the expressions of hepatic transcription factors such as liver X receptor alpha, sterol regulatory element-binding protein 1c, and carbohydrate-responsive element-binding protein alpha, as well as their target genes. In conclusion, dietary supplementation with FRB may lower hypertension and alleviate metabolic syndrome.

CONCLUSION

Metabolic syndrome was better alleviated with FRB supplementation. We therefore suggest FRB as an alternative medicine to reduce the risks of lifestyle-related diseases.

Effect of foxtail millet protein hydrolysates on lowering blood pressure in spontaneously hypertensive rats

PURPOSE

The objective of this study was to determine the effect of foxtail millet protein hydrolysates on lowering blood pressure in spontaneously hypertensive rats (SHRs).

METHODS

The protein of foxtail millet after extruding or fermenting and the raw foxtail millet was extracted and hydrolyzed by digestive protease to generate angiotensin-converting enzyme (ACE) inhibitory peptides. The potential antihypertensive effect of protein hydrolysates from foxtail millet in SHRs was investigated.

RESULTS

After 4 weeks of treatment with 200 mg peptides/kg of body weight of protein hydrolysates, blood pressure was lowered significantly, and the raw and extruded samples were more effective than the fermented samples. The serum ACE activity and angiotensin II levels in the treatment groups were significantly lower than that of the control. The percent heart weight decreased in the treatment groups.

CONCLUSION

Thus, ingestion of foxtail millet protein hydrolysates especially for the raw and extruded hydrolysates may ameliorate hypertension and alleviate related cardiovascular diseases.