The potential application of the protein hydrolysates of three medicinal plants: cytotoxicity and functional properties

Functional evaluation of encrypted bioactive peptides in protein structure helps to better understand those for using in pharmacy and food sciences. For this purpose, the total protein was extracted from Matricaria chamomilla, Ziziphora clinopodioides, and Cressa cretica, and partially purified with ammonium sulfate. Protein hydrolysates were obtained from pancreatin hydrolysis for 240 min and the enzyme hydrolysis was confirmed using the determination of hydrolysis degree and Fourier transform infrared (FT-IR) followed by the physicochemical and sensory properties were investigated. The results showed that all hydrolysates had both cytotoxic and antioxidant activities. Specifically, C. cretica hydrolysates represented cytotoxic activity against the MCF-7 cell line with the IC₅₀ of 135.21 µg/mL, while showed no significant growth inhibition effect on the HEK293 cell line. Besides, M. chamomilla hydrolysates showed the lowest bitterness value (1.125 ± 0.52). From the perspective of color investigation, M. chamomilla hydrolysates indicated the highest L^* and the lowest a^* factors. The highest turbidity and surface tension, and 10-fold more cancer cell killing effect under gastrointestinal digestion conditions were observed for M. chamomilla hydrolysates. Therefore, bioactive peptides might be formulated in designing of novel anticancer drugs or could be used in promising protocols for the production of food products with beneficial health effects.     

Fish protein hydrolysates: production, biochemical, and functional properties

Considerable amounts of fish processing byproducts are discarded each year. By developing enzyme technologies for protein recovery and modification, production of a broad spectrum of food ingredients and industrial products may be possible. Hydrolyzed vegetable and milk proteins are widely used food ingredients. There are few hydrolyzed fish protein foods with the exception of East Asian condiments and sauces. This review describes various manufacturing techniques for fish protein hydrolysates using acid, base, endogenous enzymes, and added bacterial or digestive proteases. The chemical and biochemical characteristics of hydrolyzed fish proteins are discussed. In addition, functional properties of fish protein hydrolysates are described, including solubility, water-holding capacity, emulsification, and foam-forming ability. Possible applications of fish protein hydrolysates in food systems are provided, and comparison with other food protein hydrolysates where pertinent.     

Influence of enzymatic hydrolysis,pH and storage temperature on the emulsifying properties of canola protein isolate and hydrolysates

The aim of this work was to enhance emulsification properties of canola proteins through enzymatic proteolysis and pH variaton. Canola protein isolate (CPI) and hydrolysates (CPHs) were used to form emulsions at pH 4.0, 7.0 and 9.0 followed by storage at 4 or 25 °C for 7 days. Controlled enzymatic hydrolysis led to increased peptide bond cleavage with time (0.23 g/100 g in CPI to 7.18 g/100 g after 24‐h Alcalase hydrolysis). Generally, oil droplet sizes were smaller for emulsions made at pH 9.0, which suggest better quality than those made at pH 4.0 and 7.0. Trypsin hydrolysate emulsions were the most physically stable at pH 7.0 and 9.0; in contrast, the pepsin hydrolysate emulsions were unstable at all conditions. The results suggest that selective enzymatic hydrolysis could play an important role in enhancing successful incorporation of canola proteins and peptides into food systems as protein emulsifiers.     

Solubility,functional properties,ACE‐I inhibitory and DPPH scavenging activities of Alcalase hydrolysed soy protein hydrolysates

Soy proteins are less soluble at acidic pH value, which impedes their utilisation in acidic beverages. Soy protein isolate (SPI) was hydrolysed using varying Alcalase concentrations (0.0001–2.0 U g^?1 protein) at different pHs (3.0–4.0). Degree of hydrolysis (DH) of soy protein hydrolysates (SPH) at pH 3.0, 3.5 and 4.0 were 5.0–10.7%, 2.3–6.1% and 0–5.4%, respectively, while solubilities ranged from 70.7 to 74.9%, 18.8 to 51.2% and 7.1 to 40.4%, respectively. The highest solubility (74.9%) was observed at pH 3.0 with 1.5 U Alcalase per g protein (DH = 9.2%). Emulsifying activities of SPHs at pH 3.0 and 4.0 ranged from 0.49 to 0.63 AU and 0.19 to 0.24 AU, respectively, while the emulsifying stabilities were 12.2–14.7 min and 18.7–56.0 min, respectively. The foaming capacity at pH 3.0 and 4.0 was 44.9–46.3 mL and 31.2–41.3 mL, respectively, whereas the foaming stability was 25.5–35.2 min and 12.8–15.1 min, respectively. However, hydrolysates had an insignificant effect on ACE‐I inhibitory and DPPH scavenging activities in comparison with SPI.     

奇亚籽蛋白及其活性肽的研究进展

奇亚籽富含优质蛋白质,且包含8种必需氨基酸。奇亚籽蛋白具有乳化、发泡等许多优良的功能性质,其制备的活性肽具有抗氧化、抗高血压等生物性能。本文综述了近年来国内外有关奇亚籽蛋白的氨基酸组成、提取分离工艺、功能性质、生物活性肽的制备及其生理功能方面的研究,并对奇亚籽蛋白在未来的发展方向以及在食品领域的开发应用作出了展望。     

Enzymatic hydrolysis of Nile tilapia (Oreochromus niloticus) myofibrillar proteins: effects on nutritional and hydrophilic properties

Protein concentrate (PC) was prepared from eviscerated and mechanically deboned fish. The pulp was washed sequentially with 0.05 M NaCl and 4 g l^?1 NaHCO₃ solutions, with cold ethanol and then with hot (50 °C) ethanol. Subsequently, it was dried (40 °C) and ground to 60 mesh. Enzyme (Flavourzime^®) hydrolysates were prepared with a degree of hydrolysis (DH) ranging from 3.5 to 45%. The PC was characterized for proximate composition, amino acid profile, physical and functional properties. The influence of DH on functional and nutritional properties was evaluated. Hygroscopicity increased in all hydrolysates for environmental relative humidities above 40% and solubility increased rapidly for DH above 7%. Water retention, water absorption and oil absorption all decreased as a function of DH. The pH (3 to 9) influenced the water and oil absorption of the hydrolysate with 7% DH. A pH near the isoelectric point tends to decrease water absorption but increase oil absorption capacity. The insoluble fraction (IF) of the hydrolysates presented a better amino acid profile than the soluble fraction (SF). The nutritional indexes determined for the IF did not differ from the total hydrolysate, but they were consistently higher than those for the SF. Copyright © 2003 Society of Chemical Industry     

Functional and antioxidative properties of protein hydrolysates from Cape hake by‐products prepared by three different methodologies

BACKGROUND: The production of fish protein hydrolysates (FPH) is a convenient technology for upgrading fish by‐products. The aim of this work was to study three different methods of FPH preparation from Cape hake by‐products to improve yield and quality. Functional and antioxidative properties of all FPHs were determined. RESULTS: The protein content of hake FPH was in the range 807–860 g kg^?1 and the degree of hydrolysis was between 19% and 22%. The maximum yield (71.9%) was achieved by methodology B but the hydrolysate was darker. The peptide profile of all FPHs was very similar. FPH prepared by methodology C had significantly higher emulsifying activity index and hydrolysate prepared by methodology B had the highest foaming capacity. The solubility of FPH was in the range 71–76% and increased the water‐holding capacity of minced fish by about 9%. The fractionation of FPH obtained by methodologies A and B allowed concentrating peptides with higher radical scavenging activity and reducing power. CONCLUSION: The properties of the FPH prepared indicated that they can be used in food systems as natural additives, particularly to improve their water‐holding capacity. © 2012 Society of Chemical Industry     

还原糖对牡蛎蛋白肽糖基化反应产物功能特性与抗氧化性的影响

以葡萄糖(Glc)、乳糖(Lac)、半乳糖(Gal)为糖基供体,对牡蛎蛋白多肽(OP)进行干法糖基化改性,比较分析糖基化产物(OP-GMPs)的功能特性(溶解性、热稳定性和乳化性)及抗氧化性(还原能力,DPPH·、·OH的清除能力)。结果表明,与双糖(Lac)相比,单糖(Glc、Gal)对OP的功能特性和抗氧化性改善效果较好;其中,质量比Gal:OP=2:1时,OP-GMPs的溶解性最大且对DPPH·的清除能力最强,为3:1时,其乳化性最强,为4:1时,其对·OH的清除能力最强;Glc:OP=3:1和4:1时,OP-GMPs的热稳定性和还原能力最强。因此,糖基化改性可有效改善OP的功能特性与抗氧化活性,为其在功能食品及调味品中的应用提供参考。     

Antioxidant activity,functional properties and bioaccessibility of whey protein hydrolysates

The main objective of this study was to produce the functionally improved whey protein hydrolysate with high bioaccessible antioxidant activity. The hydrolysate with highest antioxidant activity, mainly composed of hydrophilic antioxidant peptides and suitable for preventing oxidation in polar food matrices, was produced by tryptic hydrolysis conducted at 37 °C and an enzyme/substrate (E/S) ratio of 0.5%. The hydrolysate exerted significantly improved antioxidant activity (80.0%), digestibility (95.9%) and bioaccessibility (124.6%) compared to the native whey proteins (32.1%, 87.1% and 106.3%, respectively) as widely used food supplement. The high bioaccessibility indicates the preservation of hydrolysate bioactivity during the process of gastrointestinal digestion, as a particular challenge in its application.     

Comparison of functional properties of 34% and 80% whey protein and milk serum protein concentrates

This study compared the functional properties of serum protein concentrate (SPC) with whey protein concentrate (WPC) made from the same milk and with commercial WPC. The experimental SPC and WPC were produced at 34% or 80% protein from the same lot of milk. Protein contents of WPC and SPC were comparable; however, fat content was much lower in SPC compared with WPC and commercial WPC. The effect of drying methods (freeze vs. spray drying) was studied for 34% WPC and SPC. Few differences due to drying method were found in turbidity and gelation; however, drying method made a large difference in foam formation for WPC but not SPC. Between pH 3 and 7, SPC was found to have lower turbidity than WPC; however, protein solubility was similar between SPC and WPC. Foaming and gelation properties of SPC were better than those of WPC. Differences in functional properties may be explained by differences in composition and extent of denaturation or aggregation.     

美拉德反应对豌豆蛋白水解物乳化性和抗氧化性的影响

本文考察了美拉德反应对不同商业蛋白酶（碱性蛋白酶、风味蛋白酶和复合蛋白酶）制备的豌豆蛋白水解物的理化性质、乳化性和抗氧化性的影响。豌豆蛋白水解物分别与葡萄糖、麦芽糊精和葡聚糖在pH7.0,60℃保温48h。结果:体系反应48h后游离氨基含量下降;希夫碱含量增加;反应物荧光强度下降。表明,豌豆蛋白水解物与糖发生了共价结合。SDS-PAGE进一步证实了高分子共聚物的生成。美拉德反应显著提高了风味蛋白酶和复合蛋白酶水解物的乳化能力,尤其是复合蛋白酶水解物与葡聚糖的反应产物表现出了极好的乳化活性和乳化稳定性。各美拉德反应产物均具有显著抑制脂质体氧化的能力（p<0.05）。所有糖中,葡聚糖制备的反应物具有最高的乳化活性和抗氧化活性。因此,葡聚糖参与的美拉德反应可作为提高豌豆蛋白水解物乳化性的一种有效方法,并完好保留水解物的抗氧化活性。      

Chia (Salvia hispanica L.) seed mucilage as a fat replacer in yogurts: Effect on their nutritional,technological, and sensory properties

Growing consumer demand for healthy and nutritious products has motivated scientists and food manufacturers to design novel dairy products with higher fiber levels and lower fat content that are free of chemical additives. Chia seed mucilage (CSM) is a healthy natural gel extensively used as a dietary source of soluble fiber, a bulking agent, and a fat replacer in a large variety of foods. In this study, we evaluated the effect of CSM on the nutritional, technological, and sensory properties of skimmed yogurts. The addition of 7.5% CSM to a yogurt formula lowered the degree of syneresis of the resulting yogurt during storage compared with full-fat yogurts. The nutritive value of the enriched yogurts improved due to higher levels of dietary fiber compared with full-fat and skimmed yogurts. Moreover, rheological measurements revealed greater consistency, firmness, and viscosity, as well as the formation of a highly structured network and better resistance to stress in yogurts containing 7.5% CSM. The sensory acceptance of the yogurts enriched with 7.5% CSM was similar to the reference samples in acidity, creaminess, and viscosity terms. These results confirm the feasibility of using CSM as a fat replacer to design novel skimmed yogurts.     

Short communication: Chia seed extract enhances physiochemical and antioxidant properties of yogurt

Yogurt is a healthy dairy food fermented by lactic acid bacteria (LAB). Because consumers demand healthier and more nutritious yogurt, numerous substances have been used to supplement yogurt. Chia seed has been reported to contain abundant phenolic compounds, dietary fiber, and n-3 fatty acids and therefore is a potential functional food additive. The aim of this study was to investigate the influence of chia seed extracts on the physicochemical and bioactive properties of set-type yogurt. Yogurt was fortified with chia seed water extract (CSWE) or chia seed ethanol extract (CSEE) at 0.05 or 0.1% (vol/vol). Results showed that supplementation with CSWE or CSEE significantly accelerated the fermentation rate and growth of LAB. Both CSWE and CSEE improved the viscosity, syneresis, and water-holding capacity of yogurt. The radical scavenging activity of yogurt was increased with both extracts, and the 0.1% CSEE yogurt exhibited the highest radical scavenging activity. Furthermore, 0.1% CSEE yogurt significantly inhibited lipopolysaccharide-induced production of hydrogen peroxide in human colon cells. Addition of chia seed extract improves the growth of LAB, the physiochemical properties, and the health-beneficial effects of set-type yogurt.     

Camel milk protein hydrolysates with improved technofunctional properties and enhanced antioxidant potential in in vitro and in food model systems

Camel milk protein hydrolysates (CMPH) were generated using proteolytic enzymes, such as alcalase, bromelain, and papain, to explore the effect on the technofunctional properties and antioxidant potential under in vitro and in real food model systems. Characterization of the CMPH via degree of hydrolysis, sodium dodecyl sulfate-PAGE, and HPLC revealed that different proteins in camel milk underwent degradation at different degrees after enzymatic hydrolysis using 3 different enzymes for 2, 4, and 6 h, with papain displaying the highest degradation. Technofunctional properties, such as emulsifying activity index, surface hydrophobicity, and protein solubility, were higher in CMPH than unhydrolyzed camel milk proteins. However, the water and fat absorption capacity were lower in CMPH compared with unhydrolyzed camel milk proteins. Antioxidant properties as assessed by 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities and metal-chelating activity were enhanced after hydrolysis, in contrast to ferric-reducing antioxidant power which showed a decrease after hydrolysis. The CMPH were also tested in real food model systems for their potential to inhibit lipid peroxidation in fish mince and grape seed oil-in-water emulsion, and we found that papain-produced hydrolysate displayed higher inhibition than alcalase- and bromelain-produced hydrolysates. Therefore, the CMPH demonstrated effective antioxidant potential in vitro as well as in real food systems and showed enhanced functional properties, which guarantees their potential applications in functional foods. The present study is one of few reports available on CMPH being explored in vitro as well as in real food model systems.     

Physicochemical and rheological properties of interacted protein hydrolysates derived from tuna processing by-products with sodium alginate

The physicochemical properties of tuna protein hydrolysates were enhanced by interaction with sodium alginate. The increase in emulsifying capacity and stability was from 50 to 150 m² g⁻¹ and from 36 to 49 min, respectively. The increase in foaming capacity and stability was from 100% to 140% and from 65% to 70%, respectively. The reason for the increased physicochemical properties was the reduced zeta potential level of tuna protein hydrolysates after interaction with sodium alginate. The change in internal structure of tuna protein hydrolysates after interaction with sodium alginate was determined by SEM and FTIR. The SEM results showed that a net cross-linking structure was formed from a sheet structure after the tuna protein hydrolysates interacted with sodium alginate. FTIR demonstrated that parts of the β-sheet of tuna protein hydrolysates were changed into an irregular coiled structure or α-helix after interaction with sodium alginate. In order to understand the interacted complex better, the rheological properties of interacted tuna protein hydrolysates with sodium alginate were further determined. In this study, the one-step was developed, easy-to-operate and cost-effective process that can further add value to tuna protein hydrolysates derived from tuna processing by-products.     

醇法大豆浓缩蛋白的加工、性能与应用

醇法大豆浓缩蛋白在大豆蛋白产品中占有重要地位,但它在国内的发展水平还很低.为了促进我国大豆浓缩蛋白的发展,对其加工、性能和应用进行了阐述.逆流浸出法是目前较常见的醇法大豆浓缩蛋白制备方法.醇法大豆浓缩蛋白的溶解度较低,但是它有较强的持水性、持油性以及较高的黏度,通过改性可以进一步改善其功能性质.传统的醇法大豆浓缩蛋白主要应用于肉制品加工,大量的醇法大豆浓缩蛋白被加工成组织蛋白.经过改性的醇法大豆浓缩蛋白可以应用于对乳化性及持油性要求较高的高脂肪食品中.     

Spray-dried encapsulation of chia essential oil (Salvia hispanica L.) in whey protein concentrate-polysaccharide matrices

Eight chia essential oil-in-water fresh emulsions (E) variations were prepared using biopolymers blends whey protein concentrate (WPC) with mesquite gum (MG) or gum Arabic (GA), core to wall material ratios (C_o:W_a) of 1:2 and 1:3, and total solids contents (TSC) of 30 and 40 wt%. All E variations displayed volume-weighted mean size (d_4,3) droplet sizes that fell within 2.32 and 3.35 μm and rates of droplet coalescence (k_C) of 10⁻⁸ s⁻¹. E variations were spray-dried and the resulting microcapsules (M) had d_4,3 falling within the range of 13.17–28.20 μm. The encapsulation efficiency (EE) was higher than 70% for all M, but those obtained from E with lower TSC and higher C_o:W_a displayed higher EE and lower surface oil, independently of M particle size. The reconstituted emulsions (RE) exhibited significantly higher d_4,3 and k_C values of the same magnitude as E variations.