In vitro antioxidant activities of hydrolysates obtained from Iranian wild almond (Amygdalus scoparia) protein by several enzymes

A protein extract from wild almond was hydrolysed using five different enzymes (pepsin, trypsin, chymotrypsin, alcalase and flavourzyme). The hydrolysates were then assayed for their antioxidant activities. The highest extent of proteolysis was obtained with alcalase (0.35; determined as the change in the absorbance at 340 nm, ΔA₃₄₀) and the lowest was with pepsin (ΔA₃₄₀ = 0.12). Radical scavenging activities obtained by 2, 2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulphonic acid) and ferric‐reducing abilities of the hydrolysates demonstrated that the hydrolysate from alcalase had significantly (P < 0.05) greater antioxidant activity. Analysis of the molecular weight distributions showed that peptides produced by alcalase were smaller than those produced by chymotrypsin, trypsin and flavourzyme. Based on the current study, the hydrolysates produced by alcalase can be suggested as potential antioxidant agents in food industry and for use in functional foods.     

Antioxidant,immunomodulatory and antiproliferative effects of gelatin hydrolysates from seabass (Lates calcarifer) skins

This study investigated the antioxidant, immunomodulatory and antiproliferative potentials of gelatin hydrolysates from seabass skins in cell model systems. Gelatin hydrolysates were extracted from seabass skins using different processes and enzyme concentrations. The ability of the hydrolysates to protect against H₂O₂‐induced DNA damage was assessed on U937 cells using the Comet assay, and one of the samples showed DNA protective effects. All samples showed immunomodulatory potential by significantly (P < 0.05) reducing interleukin‐6 (IL‐6) and IL‐1β production in lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophage cells. Antiproliferative activities of seabass skin hydrolysates were measured using human colon cancer (Caco‐2) and liver cancer (HepG2) cell lines as the model cell cultures. The inhibition of cell proliferation of Caco‐2 and HepG2 cancer cells occurred in a dose‐dependent manner at concentrations of 1–25 mg mL^?1. Therefore, seabass skin hydrolysates prepared using an appropriate process could serve as a potential functional food ingredient with various health benefits.     

菜籽饼粕水解液为氮源细菌发酵产L-乳酸的发酵培养基优化

从降低L-乳酸生产成本和提高菜籽饼粕综合利用的角度考虑,尝试菜籽饼粕水解液为氮源利用细菌发酵产L-乳酸,在单因素及均匀试验的基础上,建立BP神经网络模型,并运用遗传算法对模型进行寻优,得出的发酵培养基最佳配方简化了培养基组成(g/L):葡萄糖110.43,菜籽饼粕(干重)水解液87.78,玉米浆21.18,柠檬酸氢二铵2.85,L-乳酸产量提高了9.30%。     

Growth promotion of Bifidobacterium and Lactobacillus species by proteinaceous hydrolysates derived from poultry processing leftovers

Bacterial growth media represent a high cost in industrial applications, and for this reason, it is economically important to find less expensive supplements to replace the traditional ones. In the present work, peptide hydrolysates obtained from poultry meat and bone residues (functional animal protein [FAP]) and from feathers (functional feather protein [FFP]) were studied to determine their ability for the production of microbial biomass with improved viability. The results obtained were compared with those obtained with other supplement nutritive compounds used in fermentation growth media. The molecular composition of the hydrolysates in terms of total and soluble nitrogen, molecular weight distribution, total and free amino acids, was determined. The growth and cellular state of Bifidobacterium and Lactobacillus strains were studied by turbidimetric measurements and direct count by fluorescence microscopy. Overall, this study suggested that by‐products from poultry industry provide a good alternative to substitute expensive supplements for growth of Lactobacillus and Bifidobacterium with a high level of viability.     

美拉德反应型蟹味香精制备条件优化及挥发性风味成分分析

以花蟹酶解液为原料,通过均匀设计实验法,结合感官评价方法,优化美拉德反应型蟹味香精的最佳配方及制备条件,并采用固相微萃取气质联用技术（SPME-GC-MS）研究反应前后的挥发性风味物质组成。研究结果表明,美拉德反应最佳参数为:以花蟹酶解液为基准,分别添加葡萄糖6.7%,木糖2.0%,甘氨酸0.6%,精氨酸2.2%,牛磺酸0.1%,硫胺素1.4%;反应温度101℃,时间33 min,p H7.5。所得反应产物呈均一的红褐色,且香气浓郁,特征风味明显,鲜味醇厚。从花蟹酶解液和反应产物中分别检测出24种和43种风味成分,反应产物中含有酮类8.82%、醛类30.87%、呋喃类18.83%、吡嗪类20.04%、醇类6.35%及一些其他的挥发性风味物质。2,3-丁二酮、3-甲硫基丙醛、2-甲基吡嗪、1-辛烯-3-醇等化合物风味阈值较低,对整体香气具有重要的贡献作用。      

预处理方式对鳙鱼骨蛋白酶解液游离氨基酸和挥发性成分的影响

对汽爆处理和热处理2种不同预处理得到的鳙鱼骨蛋白进行酶解,对所得2种鱼骨蛋白酶解液(汽爆处理标记为SFBPH,热处理标记为HFBPH)的游离氨基酸、挥发性成分和分子质量分布进行比较分析.结果 表明:SFBPH的水解度高于HFBPH,SFBPH和HFBPH中分子质量小于1000 Da的小分子分别占73.78％和66.56...     

Production and properties of casein hydrolysate microencapsulated by spray drying with soybean protein isolate

The aim of this work was to encapsulate casein hydrolysate by spray drying with soybean protein isolate (SPI) as wall material to attenuate the bitter taste of that product. Two treatments were prepared: both with 12 g/100 g solids and containing either two proportions of SPI: hydrolysate (70:30 and 80:20), called M1 and M2, respectively. The samples were evaluated for morphological characteristics (SEM), particle size, hygroscopicity, solubility, hydrophobicity, thermal behavior and bitter taste with a trained sensory panel using a paired-comparison test (non-encapsulated samples vs. encapsulated samples). Microcapsules had a continuous wall, many concavities, and no porosity. Treatments M1 and M2 presented average particle sizes of 11.32 and 9.18 μm, respectively. The wall material and/or the microencapsulation raised the hygroscopicity of the hydrolysate since the free hydrolysate had hygroscopicity of 53 g of water/100 g of solids and M1 and M2 had 106.99 and 102.19 g of water/100 g of solids, respectively. However, the hydrophobicity decreases, the absence of a peak in encapsulated hydrolysates, and the results of the panel sensory test considering the encapsulated samples less bitter (p < 0.05) than the non-encapsulated, showed that spray drying with SPI was an efficient method for microencapsulation and attenuation of the bitter taste of the casein hydrolysate.     

Angiotensin-I converting enzyme (ACE) inhibitory tripeptides from rice protein hydrolysate: Purification and characterization

In this study, angiotensin-I converting enzyme (ACE) inhibitory tripeptides from rice protein hydrolysate were purified and their properties were further characterized. Val-Asn-Pro (VNP) and Val-Trp-Pro (VWP) were successfully purified from rice protein hydrolysate through multi-step isolation and purification comprising of ultrafiltration and DA201-C macroporous adsorption resin, followed by a two-step reverse phase high performance liquid chromatography (RP-HPLC). The sequences of tripeptides were separately assayed by using automated protein/peptide sequencer. In addition, the stability of the tripeptides against ACE and simulated gastrointestinal proteases, ACE-inhibitory kinetics, and their antihypertensive effects in vivo were evaluated. Our results showed that VNP (IC₅₀ value of 6.4 μM) and VWP (IC₅₀ value of 4.5 μM) were both competitive ACE inhibitors, and stability against ACE and gastrointestinal proteases of pepsin and chymotrypsin. Furthermore, single oral administration of the tripeptides VNP and VWP at 5 mg/kg body weight in spontaneously hypertensive rats (SHRs) significantly decreased the systolic blood pressure (SBP) of 29 and 38 mmHg (P < 0.05), respectively, and the antihypertensive effects of tripeptides could last for 8 h minimally. The identified unique characterization of VNP and VWP may enable the application of rice protein hydrolysate as functional foods or pharmaceuticals against hypertension.     

Inhibitory effect of Eucalyptus globulus pretreated liquors on bioethanol production from Zymomonas mobilis NRRL B-806

Lignocellulosic wastes from agriculture are potentially useful as a low cost feedstock for production of bioethanol. During pretreatment of lignocellulosic materials, a wide range of inhibitory compounds to microorganisms are formed or released. The present work focused on production of bioethanol by Z. mobilis NRRL B-806 in different culture media. Inhibitory effects of the bio-products yielded in the pretreatment process of Eucalyptus globulus were determined. Results obtained showed that maximum bioethanol production yield Y_E/S for Z. mobilis NRRL B-806 was 87%. Ethanol production and glucose consumption were clearly affected by high inhibitors concentration present in pretreated liquors obtained by auto-hydrolysis.