Optimization of Conditions for Enzymatic Production of ACE Inhibitory Peptides from Collagen

Bovine skin gelatin hydrolysates as potential substitutes for polyphosphates: The role of degree of hydrolysis and pH on water-holding capacity

The effects of adding bovine skin gelatin hydrolysate obtained with subtilisin, on water-holding capacity (WHC), in a thermally processed chicken meat model, were investigated. Hydrolysates with different degrees of hydrolysis (DH) (6.57%, 13.14%, and 26.28%) were prepared. The results showed that all the tested hydrolysates improved water retention in the meat matrix. The hydrolysate with 26.28% DH showed similar behavior throughout the full range of concentrations [0% to 5% w/w] compared to that of the positive control (sodium tripolyphosphate [STPP]). In addition, the other hydrolysates [6.57% DH and 13.14% DH at 3% and 2.5% w/w concentrations, respectively] showed behaviors that coincided with that of STPP at its maximum limit allowed. A correlation was observed between the WHC and the pH of the meat samples treated with each hydrolysate or STPP. In addition, it was found that the WHC of the hydrolysates was due to increases in pH and the specific effects of the hydrolysate beyond the typical effects of pH and ionic strength in meat systems. The solubility of all hydrolysates was high (>90%). In conclusion, bovine skin gelatin hydrolysates could serve as an alternative to polyphosphates to improve water retention and the functional properties of thermally processed meat products. PRACTICAL APPLICATION: This study investigated the effects of adding bovine skin gelatin hydrolysate obtained with subtilisin on water-holding capacity (WHC) in a thermally processed chicken meat model. It was found that the hydrolysis of bovine skin gelatin with subtilisin can replace chemical products harmful to health, such as STPP, in terms of water-holding capacity. Therefore, bovine skin gelatin hydrolysate can be used as an ingredient in the formulation of thermally processed meat products.

Potential Antioxidant and Angiotensin I-converting Enzyme Inhibitory Activity in Crust of Dry-aged Beef

Antioxidant activity, angiotensin I-converting enzyme (ACE) inhibitory activity, and protein profile of crust (the dried surface of dry-aged beef) were evaluated compared to unaged, wet-, and dry-aged beef. Antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-di-(3-ethylbenzthiazoline sulfonate) radical scavenging activities, ferric reducing antioxidant power, and ferrous ion chelating activity. The crust samples showed the greatest (P < 0.05) ACE inhibitory and antioxidant activity resulting from the three different mechanisms of action (radical scavenging, non-radical redox potential activity, and metal chelating) among the treatments. Small molecular weight protein bands and small peptides (<3 kDa) indicating potent bioactivity were evident in the myofibrillar protein profile of crust samples. The lowest (P < 0.05) ACE inhibitory activity was observed in unaged beef. The results indicate that crust could be utilized in various areas as a functional ingredient possessed antioxidant and ACE inhibitory activity instead of being discarded. In addition, dry aging can use for generation of functional ingredient from beef as the regime.

Recent Research in Antihypertensive Activity of Food Protein-derived Hydrolyzates and Peptides

Year to year obesity prevalence, reduced physical activities, bad habits/or stressful lifestyle, and other environmental and physiological impacts lead to increase in diseases such as coronary heart disease, stroke, cancer, diabetes, and hypertension worldwide. Hypertension is considered as one of the most common serious chronic diseases; however, discovery of medications with high efficacy and without side effects for treatment of patients remains a challenge for scientists. Recent trends in functional foods have evidenced that food bioactive proteins play a major role in the concepts of illness and curing; therefore, nutritionists, biomedical scientists, and food scientists are working together to develop improved systems for the discovery of peptides with increased potency and therapeutic benefits. This review presents a recent research carried out to date for the purpose of isolation and identification of bioactive hydrolyzates and peptides with angiotensin I converting enzyme inhibitory activity and antihypertensive effect from animal, marine, microbial, and plant food proteins. Effects of food processing and hydrolyzation conditions as well as some other impacts on formation, activity, and stability of these hydrolyzates and peptides are also presented.

Production of the angiotensin I converting enzyme inhibitory peptides and isolation of four novel peptides from jellyfish (Rhopilema esculentum) protein hydrolysate

BACKGROUND

Angiotensin I converting enzyme (ACE) plays an important role in regulating blood pressure in the human body. ACE inhibitory peptides derived from food proteins could exert antihypertensive effects without side effects. Jellyfish (Rhopilema esculentum) is an important fishery resource suitable for production of ACE inhibitory peptides. The objective of this study was to optimize the hydrolysis conditions for production of protein hydrolysate from R. esculentum (RPH) with ACE inhibitory activity, and to isolate and identify the ACE inhibitory peptides from RPH.

RESULTS

Rhopilema esculentum protein was hydrolyzed with Compound proteinase AQ to produce protein hydrolysate with ACE inhibitory activity, and the hydrolysis conditions were optimized using response surface methodology. The optimum parameters for producing peptides with the highest ACE inhibitory activity were as follows: hydrolysis time 3.90 h, hydrolysis temperature 58 °C, enzyme:substrate ratio 2.8% and pH 7.60. Under these conditions, the ACE inhibitory rate reached 32.21%. In addition, four novel ACE inhibitory peptides were isolated, and their amino acids sequences were identified as Val-Gly-Pro-Tyr, Phe-Thr-Tyr-Val-Pro-Gly, Phe-Thr-Tyr-Val-Pro-Gly-Ala and Phe-Gln-Ala-Val-Trp-Ala-Gly, respectively. The IC50 value of the purified peptides for ACE inhibitory activity was 8.40, 23.42, 21.15 and 19.11 µmol L(-1) .

CONCLUSION

These results indicate that the protein hydrolysate prepared from R. esculentum might be a commercial competitive source of ACE inhibitory ingredients to be used in functional foods. © 2015 Society of Chemical Industry.

Antimicrobial and radical scavenging properties of bovine collagen hydrolysates produced by Penicillium aurantiogriseum URM 4622 collagenase

A 2(3) full factorial design was used to identify the main effects and interactions of pH, collagen concentration and temperature on the degree of collagen hydrolysis (DH) by collagenase from Penicillium aurantiogriseum URM 4622. Increases in both pH and collagen concentration improved DH, and a positive interaction effect was observed for these variables. On the other hand, temperature had a negative main effect on DH. The maximum value of DH (4.65 μg/mL) was achieved at 7.5 mg/mL collagen concentration, pH 8.0 and 25 °C. The peptide profile showed several peptides with molecular weights lower than 2 kDa and exhibited antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. An antioxidant activity of 84.7 ± 0.24 % towards the radical ABTS• + was obtained with 50 mg/mL hydrolysates. This study demonstrated that collagen hydrolysed by P. aurantiogriseum URM 4622 collagenase possesses interesting antibacterial and antioxidant activities.

Novel aspects of health promoting compounds in meat

Meat is an integral part of the human diet. Besides essential amino acids and nutritive factors of high quality and availability, meat provides often overlooked components of importance for human health. These are amino acids and bioactive compounds that may be very important in i) preventing muscle wasting diseases, such as in sarcopenia, ii) reducing food and caloric intake to prevent metabolic syndrome, iii) blood pressure homeostasis via ACE-inhibitory components from connective tissue, and iv) maintaining functional gut environment through meat-derived nucleotides and nucleosides. In addition, meat could be an important source of phytanic acid, conjugated linoleic acids and antioxidants. Further, it becomes increasingly apparent that design of in vitro meat will be possible, and that this development may lead to improved health benefits from commercially viable and sustainable meat products.

Accumulation and identification of angiotensin-converting enzyme inhibitory peptides from wheat germ

The incubation conditions of wheat germ for angiotensin I-converting enzyme inhibitory activity (ACEI) elevation and peptide accumulation were investigated, and five ACE inhibitory peptides were obtained. The effect of individual factors such as incubation time, temperature, initial pH, and liquid to solid ratio on ACEI and peptide concentration of incubation medium was evaluated, respectively. The combinations of four factors were further optimized using a Box-Behnken design. Under the best incubation condition (pH 4.4 with a liquid to solid ratio 8.14 mL/g at temperature 47 °C, for 7 h), maximum ACEI (92.16%) and peptide concentration (88.12 mg/g) were obtained, which were 6.2- and 2.4-fold, respectively, as compared to the unincubated wheat germ. After they were purified, five ACE inhibitory peptides, VEV, W, NPPSV, QV, and AMY, were identified by liquid chromatography/tandem mass spectrometry. The IC(50) were 115.20, 94.87, 40.56, 26.82, and 5.86 μM, respectively.