Structural characteristics of oligosaccharides from soy sauce lees and their potential prebiotic effect on lactic acid bacteria

Oligosaccharides have attracted much attention due to the beneficial health effect on human beings. Oligosaccharides were extracted from soy sauce lees (SSLO) and were purified in this work. It was a mixture of oligosaccharides, which accounted for 80.5% of the total weight, and free monosaccharides. Only two monosaccharides, xylose and mannose, were detected in the molecular chain of SSLO. Their relative molar percentages were 53.2% and 46.8% for the oligosaccharide and monosaccharide fractions, respectively. A dose-dependent behaviour was observed for the growth promoting effect of SSLO on Lactobacillus bulgaricus and Streptococcus thermophilus. When 200 μg/ml of SSLO was applied, the L. bulgaricus concentration was 15.7-fold higher than the control, whilst the S. thermophilus concentration was 34.7-fold higher than the control. The analysis of DPPH radical scavenging activity indicated poor antioxidant activity of SSLO. It also suggested that the prebiotic effect was not correlated with antioxidant activity.     

Microbial composition during Chinese soy sauce koji-making based on culture dependent and independent methods

Koji-making is a key process for production of high quality soy sauce. The microbial composition during koji-making was investigated by culture-dependent and culture-independent methods to determine predominant bacterial and fungal populations. The culture-dependent methods used were direct culture and colony morphology observation, and PCR amplification of 16S/26S rDNA fragments followed by sequencing analysis. The culture-independent method was based on the analysis of 16S/26S rDNA clone libraries. There were differences between the results obtained by different methods. However, sufficient overlap existed between the different methods to identify potentially significant microbial groups. 16 and 20 different bacterial species were identified using culture-dependent and culture-independent methods, respectively. 7 species could be identified by both methods. The most predominant bacterial genera were Weissella and Staphylococcus. Both 6 different fungal species were identified using culture-dependent and culture-independent methods, respectively. Only 3 species could be identified by both sets of methods. The most predominant fungi were Aspergillus and Candida species. This work illustrated the importance of a comprehensive polyphasic approach in the analysis of microbial composition during soy sauce koji-making, the knowledge of which will enable further optimization of microbial composition and quality control of koji to upgrade Chinese traditional soy sauce product.     

Anti-hydrogen peroxide activity of fish and soy sauce

Shoyu is the Japanese name for soy sauce and the most popular liquid condiment (seasoning) used in Japanese cuisine as well as in cuisines of other oriental countries. Shoyu is prepared by digesting mold-cultured soybeans and wheat seeded with an aspergillus (koji in Japanese) in the presence of sodium chloride. Gyoshoyu is produced when the soybeans and wheat are replaced with fish. Both Shoyu and Gyoshoyu have high level of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. Hydrogen peroxide is produced in green tea after exposure to air. To find a safe and economical method of preventing the production of H₂O₂ in green tea, effects of Shoyu and Gyoshoyu on H₂O₂ level in bottled green tea were examined. Both Shoyu and Gyoshoyu suppressed the production of H₂O₂. Gyoshoyu decomposed H₂O₂ possibly because of the presence of a thermostable catalase, while Shoyu did not. Some components of Shoyu and Gyoshoyu may be useful to suppress the production of H₂O₂ in green tea.     

A study of chemical characteristics of soy sauce and mixed soy sauce: chemical characteristics of soy sauce

Mixed soy sauce is one among the Korean traditional fermented soy sauces consumed as condiment for cooking in Korea, especially mixed soy sauce is made of the fresh seafood and the meat different from the soy sauce. Therefore, mixed soy sauce provides the strong and complicated umami taste, which is stronger than that of soy sauce. The objective of this study was to investigate for the chemical characteristics changes of mixed soy sauce in comparison with soy sauce during fermentation process (0, 120, 240 and 360 days) at different fermentation temperatures (4 and 20 °C), change in moisture, total nitrogen, crude fat, ash, pH, titratable acidity, total acidity, salt content and reducing sugar of mixed soy sauce in comparison with soy sauce. Especially, histidine, arginine, threonine, methionine, phenylalanine, and lysine, essential amino acid and among adenosine triphosphate (ATP)-related compounds, inosine (HxR) and hypoxantine (Hx) were prominent in mixed soy sauce at 20 °C. Otherwise, 2,4-dinitrophenylhydrazine (DNPH) derivative and 3DG content were prominent in soy sauce at 20 °C. The content of 2,4-DNPH derivative and 3DG in soy sauce is correlated with its browning intensity.     

酱油中氨基酸的理化性质

重点讨论了氨基酸的一般物理性质和化学性质，及酱油内的氨基酸在一定条件下的化学变化。     

Aggregation of hydrophobic soybean protein hydrolysates: Changes in molecular weight distribution during storage

The stability and molecular weight of peptides play important roles in their functional and biological properties. In this study, soybean protein hydrolysates (SPHs) with different hydrophobic characteristics were used to evaluate the aggregation of peptides during storage at −20 °C. SPHs were isolated from immobilized metal affinity chromatography, and size expulsion HPLC showed the molecular weight distribution of them at different storage times. As time elapsed, some high molecular weight peptides formed from the original SPHs, and the content of the newly formed high molecular weight peptides produced from the highly hydrophobic SPHs was considerably large. The aggregation could be broken by 6 mol/l urea and 20 g/l SDS. The damage caused by 6 mol/l urea was stronger than that of 20 g/l SDS. The results suggested that hydrophobic interaction may promote the aggregation of SPHs during storage.     

"移位浸出法"和"原池淋浇浸出法"在低固酱油生产中的对比

对比分析了移位浸出法和原池淋浇浸出法这两种方法在低盐固态酱油生产工艺中的应用。原池淋浇浸出法优于移位浸出法。     

酱货架期美拉德反应机理的研究

分析了不同品牌酱类产品的理化指标,选取有代表性的样品作为研究对象,根据Arrhenius和ASLT理论,采用保温加速试验,将目标酱在50℃保温,模拟正常储存条件下各项指标的变化,分析其在货架期的变化趋势,研究发现:酱在保温过程中由于美拉德反应,导致总酸明显升高,氨基态氮下降,产生CO2气体等现象,而酱中的还原糖并没有显著降低,经验证证实,是由于美拉德反应导致了酱的pH缓慢降低,在低pH条件下,酱中的白糖逐步分解为还原糖,反而使体系中的还原糖水平保持在一个高的水平,进一步促进美拉德反应的进行,虽然少量的Na2SO3和CaCl2,可以明显的抑制美拉德反应的速度,但为了保证酱的食品安全,最好采用纯天然的含有抑制剂的原料来控制酱的美拉德反应。     

Determination of levulinic acid in soy sauce by liquid chromatography with mass spectrometric detection

A novel method using liquid chromatography coupled with mass spectrometry (LC–MS) was developed for the determination of levulinic acid (LV) in soy sauces to identify the addition of acid hydrolyzed vegetable protein (acid-HVP). One hundred percentage naturally brewed soy sauce (NBS) and enzymatic hydrolyzed vegetable protein (enzymatic HVP) did not contain LV (<0.01 mg/mL). There was apparent detection of LV in acid-HVP and blended soy sauce with acid-HVP (2.98–21.66 mg/mL). Gas chromatography (GC) and high performance liquid chromatography (HPLC) at 430 nm methods were also investigated. The results by GC gave similar data to those by LC–MS. In enzymatic HVP, LV was detected by HPLC at 430 nm, but it was confirmed that the detected component was not in fact LV by mass spectrometric identification of the isolated peak compound. We found that LV is under the detection limit in enzymatic HVP. This study showed that LV is below the detection limit in NBS and enzymatic HVP and is apparently detected in acid-HVP and blended soy sauces with acid-HVP. These results indicate that LV is a practical index of blend with acid-HVP and also corresponds with the JAS (Japanese Agricultural Standard) or CNS (Chinese National Standard) criteria in which the presence of LV in soy sauces indicates adulteration with acid-HVP. The LC–MS method is analytically optimal for the precise determination of LV, because peak misidentification may be practically eliminated.     

Amino acid components of lees in salmon fish sauce are tyrosine and phenylalanine

We report that the lees in salmon fish sauce consist of Tyr and Phe. The concentration of free l-Tyr (2.0 mM) was almost same as the saturated concentration (2.4 mM) in water at 20°C. This result shows that lees are formed by Tyr precipitation due to its saturation in the sauce.     

酱油发酵前期微生物变化及其主要香味物质分析

以传统工艺制作的酱油,在自然发酵的环境中接入纯培养的米曲霉与鲁氏接合酵母,利用稀释平板计数法,研究其发酵过程中霉菌、酵母菌和乳酸菌数量的变化,通过气相色谱法进行呈味物质的分析.试验发现,霉菌的数目在发酵过程中呈逐渐下降的趋势;乳酸菌和酵母菌在酱油发酵初始阶段数量较少,分别为1.2×103CFU/g和7.6×102CFU/g,随着发酵时间的延长,菌数急速增加,在发酵6、7 d达到最高值,数量分别为2.4×108CFU/g和3.2×106CFU/g,此后数量逐渐下降,在第15天降到103CFU/g左右时,数量不再随时间变化;酱油的呈味物质中含有愈创木酚,其含量在发酵28 d后达到所有呈味物质的0.136 5%.     

Sweet potato protein hydrolysates: antioxidant activity and protective effects on oxidative DNA damage

In this study, sweet potato protein (SPP) hydrolysates were prepared by six enzymes (alcalase, proleather FG‐F, AS1.398, neutrase, papain and pepsin). The antioxidant activities and protective effect against oxidative DNA damage of SPP hydrolysates were investigated. Alcalase hydrolysates exhibited the highest hydroxyl radical‐scavenging activity (IC₅₀ 1.74 mg mL^?1) and Fe²⁺‐chelating ability (IC₅₀ 1.54 mg mL^?1) (P < 0.05). Compared with other five hydrolysates, the hydrolysates obtained by alcalase had the most abundant <3‐kDa fractions. In addition, below 3‐kDa fractions of alcalase hydrolysates showed the highest antioxidant activities and protective effects against DNA damage through both scavenging hydroxyl radicals and chelating Fe²⁺, which was probably because of the increase in several antioxidant amino acids, such as His, Met, Cys, Tyr and Phe, as well as the hydrophobic amino acids. The results suggested that enzymatic hydrolysis could be used as an effective technique to produce high value‐added peptides products from SPP.     

Amino acid composition,antioxidant and functional properties of protein hydrolysates from the roe of rainbow trout (Oncorhynchus mykiss)

A fish roe protein hydrolysate from rainbow trout (Oncorhynchus mykiss) trout roe protein hydrolysates (TRH) was produced by pepsin and Alcalase. Proximate, amino acid compositions, protein digestibility and molecular mass distribution of the hydrolysates were determined. The degree of hydrolysis was found to be 44.08% and 27.62% (pepsin and Alcalase, respectively). The two hydrolysates contained a high amount of essential amino acids (33.53% Alcalase–29.39% pepsin). The results showed that TRH by different enzymes is a good source of the leucine and lysine amino acids. The pepsin produced a white powder with higher brightness (L* = 89.50). Alcalase hydrolysate was brownish yellow in colour (L* = 52.85, a* = 10.30, b* = 26.25). The hydrolysates represented excellent antioxidant activities in various concentrations. TRHs showed a good foaming and emulsification properties. The results thus revealed that protein hydrolysates from rainbow trout roe could be used as food additives possessing essential amino acids and antioxidant activity.     

亟待制定酿造酱油、食醋和配制酱油、食醋统一的完善的标准(上)

提出了制定酿造酱油食醋和配制酱油食醋统一完善的标准的必要性。阐述了酱油类通过氨基酸态氮与全氮的比值比较法和食醋类通过总酸、不挥发酸等成分百分比比较法确定酿造、配制酱油、食醋的依据及具体制定方法，对新标准的制定和完善具有一定的参考价值。     

低分子量透明质酸的制备及其抗氧化活性的研究

首先研究了Fe2+-S2O2-8氧化体系硫酸根自由基(SO-4·)对透明质酸(HA)的氧化降解作用,初步确定了SO-4·氧化降解HA制备低分子量透明质酸(LMWHA)的实验条件。接着HA降解产物经过乙醇沉淀以及凝胶柱层析纯化,采用高效凝胶过滤色谱法(HPGFC)测得纯化后LMWHA分子量为1.45×105Da。最后采用不同的体外抗氧化实验,并以HA为对照,研究了LMWHA的抗氧化活性,发现SO-4·降解后生成的LMWHA的抗氧化活性高于降解前的。本实验说明用SO-4·降解HA制备具有抗氧化活性LMWHA是可行的,为LMWHA抗氧化药物的开发提供了理论依据。     

Nutritional composition and antioxidant properties of protein hydrolysates prepared from echinoderm byproducts

Protein hydrolysates were prepared from echinoderm byproducts, including viscera (SCV) of Atlantic sea cucumber ( Cucumaria frondosa ) and digestive tract (UDT) and non-commercial grade gonads (UGN) of green sea urchin ( Strongylocentrotus droebachiensis ). Enzymatic hydrolysis was performed on defatted materials using Alcalase^® 2.4L (0.75% w/w) and reaction was carried out overnight (∼16 h, 55 °C, pH 8.0). Freeze-dried hydrolysates were analysed for their nutritional composition, nitrogen solubility index and antioxidant activity. Degree of hydrolysis was low, with values of 5.6%, 4.6% and 7.0% for SCV, UDT and UGN, respectively. Hydrolysates showed high protein content (∼55%), high proportion of essential amino acids (∼35% of total amino acids) and good solubility (nitrogen solubility index ≈ 68%). They contained variable concentrations of major and trace elements with a predominance of Na and K. Hydrolysates showed apparent antioxidant activities in both ORAC assay (267–421 μmol TE g⁻¹) and inhibition of lipid oxidation test (54–57%). Antioxidant activities were thought to be associated with the presence of antioxidant peptides in hydrolysates. Our results showed that hydrolysates from Atlantic sea cucumber and green sea urchin byproducts might serve as alternative sources of dietary proteins, with good nutritional composition, high solubility and interesting protection against oxidative stress.     

凡纳滨对虾肌肉蛋白质组成及分子量分布研究

为了合理利用凡纳滨对虾蛋白质,对凡纳滨对虾肌肉进行蛋白分离,利用氨基酸自动分析仪检测蛋白的氨基酸组成及用SDS-聚丙烯酰胺电泳测定分子量分布。实验结果表明:总蛋白为(19.72±0.08)g/100g湿重,其中盐溶蛋白64.30%、水溶性蛋白25.00%、基质蛋白5.78%、非蛋白氮4.92%;凡纳滨对虾各蛋白氨基酸比例存在一定差异,但它们的第一限制氨基酸类似;SDS-PAGE电泳显示,凡纳滨对虾基质蛋白分子量分布范围较宽,集中在200~19ku,盐溶蛋白分子量集中在200~45ku,水溶性蛋白分子量集中在80~27ku。     

Immunological functions of soy sauce: hypoallergenicity and antiallergic activity of soy sauce

Soy sauce is a traditional fermented seasoning of East Asian countries and is available throughout the world. In Japanese soy sauce (shoyu), soybeans and wheat are the two main raw materials, used in almost the same quantity. Proteins of the raw materials are completely degraded into peptides and amino acids by microbial proteolytic enzymes after fermentation, and no allergens of the raw materials are present in soy sauce. In contrast, polysaccharides originating from the cell wall of soybeans are resistant to enzymatic hydrolyses. These polysaccharides are present in soy sauce even after fermentation and termed shoyu polysaccharides (SPS). Soy sauce generally contains about 1% (w/v) SPS and SPS exhibit potent antiallergic activities in vitro and in vivo. Furthermore, an oral supplementation of SPS is an effective intervention for patients with allergic rhinitis in two double-blind placebo-controlled clinical studies. In conclusion, soy sauce would be a potentially promising seasoning for the treatment of allergic diseases through food because of its hypoallergenicity and antiallergic activity.     

酱油渣中异黄酮提取工艺优化及其抗氧化性的研究

以脱脂酱油渣干粉为原料,采用响应面法优化酱油渣中异黄酮的提取工艺,并测定其抗氧化性.结果表明,最佳提取工艺条件为:以94%(v/v)乙醇为溶剂,液料比17:1(mL/g),提取温度60℃,提取时间2h.在此条件下酱油渣异黄酮的提取得率为1.14%(脱脂干基).酱油渣异黄酮提取物的ABTS+·清除能力及螯合金属离子能力显著高于黄豆异黄酮提取物,二者的DPPH·清除能力及还原力相当.     

高效液相色谱法测定酱油及食醋中的苯甲酸和山梨酸

建立了一种用高效液相色谱法快速测定酱油及食醋中苯甲酸和山梨酸的方法.使用的色谱柱为Agillent C18柱,流动相为乙酸胺:甲醇(93:7,v/v),检测波长230nm.苯甲酸和山梨酸标准溶液在2.5mg/L～50mg/L内线性良好,其线性相关系数分别0.9991和0.9984.加标回收率分别为91.7％和98.7％,测量结果的相对标准偏差(RSD)为2.77％和3.55％,苯甲酸和山梨酸的检测限分别为0.90mg/kg和0.85mg/kg.该法简单,快速,具有良好的准确度和灵敏度.