Headspace volatiles along with other instrumental and sensory analyses as indices of maturation of horse mackerel miso

Development of aroma-active compounds during fermentation in the preparation of fermented fish-meat paste product (fish miso) from horse mackerel meat was quantitatively determined and characterized by olfactometric and organoleptic assessments. The critical ripening time was estimated by quantitative and/or qualitative analyses of volatile compounds, peptides, amino acids, product color, and total phenolics of the fish miso matrix throughout fermentation. The results confirmed that the application of koji for the fermentation of horse mackerel meat to produce fish miso significantly reduced the fishy off odor and promoted the development of highly acceptable fish miso with a nutty, cheesy, and fruity aroma. Ethyl acetate, ethyl heptanoate, ethyl decanoate, 2-methylpropanal, 3-methylbutanal, 2,3-butanedione, dimethyl trisulfide, and 3-(methylthio) propanal were identified as key odor-active compounds in fish miso prepared from horse mackerel meat. Among the volatiles, 2-methylpropanal, 3-methylbutanal, and 2,3-butanedione were identified to serve as potential indicators of the maturation of fish miso. Amino acid content could also be a potential indicator of maturation of protein-rich, fermented products such as fish miso. In addition, surface color analysis of fish miso revealed a high correlation between sensory attributes and color components. Specifically, r and b values were considered potential indicators of maturation. Practical Application: Variability is a major drawback in fermented products such as fish miso and it requires establishing the optimum ripening time, defined as that providing the aroma attributes qualitatively and quantitatively mostly appreciated by consumers. We have carried out this work for comprehensive determination of the critical ripening time by applying several instrumental and sensory tools including quantitative and/or qualitative analysis of volatile compounds, peptides, amino acids, product color, and total phenolics of the fish miso matrix throughout the fermentation period. The outcome of the present study can be efficiently applied for detection of maturation in similar types of fermented product for large-scale production.     

Studies on the performance of a new bioreactor for improving antioxidant potential of rice

In the present investigation, we studied the performance of a self-designed new bioreactor (NB) for the improvement of phenolics and antioxidant activity in rice koji and the results were compared with the conventional solid-state fermentation (SSF). The non-fermented (control) and fermented masses obtained from two fermenters were extracted with water, methanol and ethyl acetate. Interestingly, rice fermented in NB resulted in a higher yield of phenolics and DPPH (1-1 Diphenyl-2-picryl hydrazyl) scavenging activity in each of the extraction media as compared to SSF and control. This might be due to the higher titre values of β-glucosidase (62.7%) and α-amylase (40.7%) in the extraction media of NB compared to SSF. It was verified by in vitro assay for phenolic enrichment in presence of α-amylase and β-glucosidase using rice as the substrate. An interesting finding was that though polyphenol content was maximum in ethyl acetate fraction, fractions extracted with water showed the highest antioxidant activity under all fermentation conditions, presumably because of the different phenolic composition which was substantiated by studying the antioxidant values of the extracts with same phenolic content in the antioxidant assay system.     

7株米曲霉与沪酿3.042发酵制备郫县豆瓣用甜瓣子的对比研究

为了筛选高效的具有潜在应用价值的郫县豆瓣生产专用米曲霉菌株,研究了7株高产蛋白酶、α-淀粉酶的米曲霉试验菌株(24M-1、21M-2、25M-1、19M-2、BM-2、18M-1、DM1)与沪酿3.042米曲霉在制备甜瓣子中的发酵性能差异,考察了不同菌株发酵的种曲中中性蛋白酶、酸性蛋白酶、α-淀粉酶的酶活力差别;进一步评价了由试验菌株制作的种曲发酵的甜瓣子的氨基酸态氮、总酸、挥发性风味物质、感官评价等发酵特性指标。结果表明,菌株24M-1、DM1发酵甜瓣子的各项发酵特性指标表现突出,甜瓣子的综合品质较佳,明显优于沪酿3.042米曲霉发酵的甜瓣子,可进一步优化菌株培养条件及发酵工艺参数,为其在郫县豆瓣加工中的应用奠定了基础。     

非耐盐乳酸菌与米曲霉共生酿造酱油的研究

文章将米曲霉与非耐盐的乳酸菌——融合魏斯氏菌(Weissella confusa)共同制曲,研究了其对制曲过程中主要酶系活力和发酵过程中质量指标、酚类物质和抗氧化活性等的影响,结果显示:酸性蛋白酶、纤维素酶、果胶酶、β-葡萄糖苷酶的活力较米曲霉组有显著提高,而中性蛋白酶活和α-淀粉酶活没有显著变化。添加了乳酸菌后的酱油不仅提高了酱油中氨基酸态氮、总氮、还原糖的含量,同时酱油中总多酚和总黄酮含量及自由基清除能力都显著增加,而有机酸含量变化较小。     

Role of Carbohydrate-Cleaving Enzymes in Phenolic Antioxidant Mobilization from Whole Soybean Fermented with Rhizopus oligosporus

Previous research has suggested a relationship between free phenolic content and β-glucosidase activity in solid-state fermented food substrates and to amylase activity in germinating soybeans. This study was undertaken to examine the role of a number of carbohydrate-cleaving enzymes in phenolic antioxidant mobilization from whole soybean during solid-state fermentation. In addition to total soluble phenolic content, α- and β-glucosidase, α-amylase, and β-glucuronidase activities were measured in extracts of soybean fermented with a food-grade fungus, Rhizopus oligosporus. Antioxidant activity of the extracts was determined as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability. Our results demonstrate that while total soluble phenolic content increased 120–135% in the extracts, increased antioxidant activity (+61%) was limited to the early fermentation period, with activity decreasing with increased culture time. Higher antioxidant activity was linked to increased glucosidase and glucuronidase activities, while high total phenolic content partly linked to increased amylase activity. The overall results (enzymatic activities and phenolic antioxidant contents) suggest the possible involvement of lignin remobilization and/or degradation activities, as well as phenolic detoxification activities, by Rhizopus oligosporus in phenolic antioxidant mobilization from fermented whole soybean.     

从自然发酵小麦酱中筛选曲霉及制曲工艺研究

从自然发酵的小麦酱中分离得到4株黄曲霉（Aspergillus flavus）和2株黑曲霉（Aspergillus niger）,对其进行生理效价分析,结果表明,黄曲霉4号产糖化型淀粉酶和蛋白酶能力最强,且具有较强的产α-淀粉酶和酯化酶的能力,适合作为小麦酱制曲的发酵菌株。对其制曲工艺进行优化,结果表明,在接种量为4%,制曲温度为32 ℃,制曲时间为70 h的条件下,小麦曲的蛋白酶酶活力为549 U/g,较自然发酵制曲的481 U/g有较大提高。     

Germinated grains - Sources of bioactive compounds

Germination of seven selected commercially important grains was studied to establish its effects on the nutritional and chemical composition. The changes in the concentration of the nutrients, bioactive compounds and the inhibitory effect of extracts on α-glucosidase and α-amylase activities were investigated. These were measured through proximate analysis, inhibition assays and HPLC. Germinated sorghum and rye extracts inhibited (p<0.05) α-glucosidase activity, whereas barley and sorghum extracts exhibited higher inhibitory activities against α-amylase. Germinated grains contained substantial amounts of total phenolics with rye having significantly higher content compared with the non-germinated grains. Radical scavenging activities of the phenolic extracts were between 13% and 73% for non-germinated and 14% and 53% for germinated. Inositol phosphate (InsP) 4, 5 and 6 were noted in all the grains, but InsP 6 was significantly lower in concentration. This study indicates the potential of germinated barley, sorghum and rye for the development of effective physiologically bioactive compounds for the reduction of the risk of diabetic agents and colon cancer.     

Changes in selected physical property and enzyme activity of rice and barley koji during fermentation and storage

Koji are solid-state fermentation products made by inoculating steamed grains with the spores of fungi, particularly Aspergillus spp. This research was undertaken to identify the fermentation and storage conditions optimal for the production and maintenance of selected hydrolytic enzymes, such as α-amlyase and protease, in koji. Steamed rice and barley were inoculated with 2 × 10 (11) Aspergillus oryzae spores per kilogram of grains and fermented for 118 h in a growth chamber at 28 to 32 °C with controlled relative humidities. Samples were drawn periodically during fermentation and storage at -20, 4, or 32 °C, and α-amylase and protease activity, mold counts, a(w), moisture contents, and pH of collected samples were determined. It was observed that the a(w), moisture contents, and pH of the koji were influenced by the duration of fermentation and temperature of storage. The α-amylase activity of both koji increased as the populations of A. oryzae increased during the exponential growth phase. The enzyme activity of barley koji was significantly higher than that of rice koji, reaching a peak activity of 211.87 or 116.57 U at 46 and 58 h, respectively, into the fermentation process. The enzyme activity in both products started to decrease once the mold culture entered the stationary growth phase. The protease activities of both koji were low and remained relatively stable during fermentation and storage. These results suggest that rice and barley koji can be used as sources of α-amylase and desired enzyme activity can be achieved by controlling the fermentation and storage conditions. PRACTICAL APPLICATION: Amylases and proteases are 2 important hydrolytic enzymes. In the food industry, these enzymes are used to break down starches and proteins while reducing the viscosity of foods. Although amylases and proteases are found in plants and animals, commercial enzymes are often produced using bacteria or molds through solid state fermentation, which is designed to use natural microbial process to produce enzymes in a controlled environment. A properly produced and maintained koji with a high hydrolytic enzyme activity can serve as an important source of the enzymes for the food industry.     

Seasonal influence on phenolic-mediated antihyperglycemic properties of Canadian sugar and red maple leaves using in vitro assay models

Red and sugar maple leaves collected in the summer and fall from Canada, were evaluated for phenolic content, antioxidant, α-glucosidase, and α-amylase inhibitory activities variation. The phenolic contents of summer red maple leaves (RML-S) and summer sugar maple leaves (SML-S) were higher than red and sugar maple leaves collected in fall (RML-F and SML-F, respectively). HPLC analyses showed differences in phenolic compounds present in the SML samples compared to the RML samples. The extracts were assayed for yeast and rat α-glucosidase inhibitory activities. Both results showed that SML-S extracts had the highest inhibitory activity which could possibly be attributed to the unique phenolics present therein. Milder effects were observed in terms of α-amylase inhibitory activity, with RML-F having the highest inhibitory activity. These results suggest that maple tree leaf extracts may have potential for phenolic-mediated α-glucosidase inhibition, relevant to type 2 diabetes management, with SML-S extract having the highest bioactivity.     

黑曲霉发酵牛蒡根的化学成分及对α-葡萄糖苷酶和α-淀粉酶抑制作用

为明确黑曲霉(Aspergillus niger)发酵对牛蒡(Arctium lappa)根的化学成分及其降糖活性的影响,本文采用黑曲霉发酵牛蒡根,分析不同发酵时间不同的发酵品对α-葡萄糖苷酶和α-淀粉酶抑制作用和化学成分的变化.酶抑制实验结果表明,牛蒡根对α-葡萄糖苷酶和α-淀粉酶的抑制作用随发酵时间延长而增强,牛蒡...     

EVALUATION OF RED CURRANTS (RIBES RUBRUM L.), BLACK CURRANTS (RIBES NIGRUM L.), RED AND GREEN GOOSEBERRIES (RIBES UVA-CRISPA) FOR POTENTIAL MANAGEMENT OF TYPE 2 DIABETES AND HYPERTENSION USING IN VITRO MODELS

Red currants (Ribes rubrum L.), black currants (Ribes nigrum L.), red and green gooseberries (Ribes uva-crispa) were evaluated for the total phenolics, antioxidant capacity based on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay and functionality such as in vitro inhibition of α-amylase, α-glucosidase and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. The total phenolics content ranged from 3.2 (green gooseberries) to 13.5 (black currants) mg/g fruit fresh weight. No correlation was found between total phenolics and antioxidant activity. The major phenolic compounds were quercetin derivatives (black currants and green gooseberries) and chlorogenic acid (red currants and red gooseberries). Red currants had the highest α-glucosidase, α-amylase and ACE inhibitory activities. Therefore red currants could be good dietary sources with potential antidiabetes and antihypertension functionality to compliment overall dietary management of early stages of type 2 diabetes.     

Anti-Diabetic Potential of Phenolic Compounds: A Review

Starch is the main carbohydrate in human nutrition. Starch digestibility can vary from a rapid digestion to indigestibility. Therefore, postprandial glycaemic control in type 2 diabetics is of great interest in the context of worldwide health concerns. Although powerful synthetic inhibitors of starch digestive enzymes, such as acarbose, are available to control postprandial hyperglycemia, plant-based enzyme inhibitors are potentially safer. Natural enzyme inhibitors, such as wheat albumin, the Phaseolus vulgaris α-amylase inhibitor, and several phenolic compounds, have the potential to serve as a remedy against hyperglycemia-induced chronic diseases. The inhibition of α-amylase and α-glucosidase is mediated by different phenolics found in varieties of raspberry. Maltase inhibitory activities of chebulagic acid and chebulinic acid from fruit of Terminalia chebula are comparable to that of acarbose. The Nepalese herb Pakhanbhed (Bergenia ciliata) phenolics, (-)-3-O-galloylepicatechin and (-)-3-O-galloylcatechin, showed effective inhibition against starch digesting enzymes. In separate studies, oral administration of starch and maltose with persimmon (Diospyros kaki) leaf tea proanthocyanidins [containing (-)-epigallocatechin-3-O-gallate] and black/bitter cumin (Centratherum anthelminticum) seed phenolics, respectively, resulted in a significant and dose-dependent decrease in the blood glucose level in Wistar rats. Co-application of phenolics with synthetic enzyme inhibitors may reduce the effective dose of synthetic inhibitors required in the regulation of starch digestion. Several phenolic compounds might be useful functional food components and could contribute to manage both hyperglycemia and proper cellular redox status. Human dose-selecting studies and well-controlled long-term human studies would help to optimize the beneficial effects of phenolic compounds.     

Anti-Diabetes Functionality of Kefir Culture-Mediated Fermented Soymilk Supplemented with Rhodiola Extracts

Natural α-amylase and α-glucosidase inhibitors from food-grade plants offer an attractive strategy to manage of postprandial hyperglycemia for Type II diabetes. Inhibition of Angiotensin I-Converting Enzyme (ACE) is also considered useful as a therapeutic approach in the treatment of high blood pressure, one of the long-term complications of diabetes. In the current study, we evaluated the inhibitory activity of phenolic extracts produced during Kefir culture-mediated fermentation of soymilk supplemented with Rhodiola extracts against α-amylase, α-glucosidase and angiotensin converting enzyme (ACE). We also investigated phenolic-linked antioxidant activity and content of salidroside and tyrosol with fermentation time.

α-Glucosidase inhibitory activity increased moderately with fermentation after 24 h and correlated to increased tyrosol and reduced salidroside contents. α-Amylase inhibitory activity decreased to zero with fermentation time, and the initial high activity prior to fermentation strongly correlated to high salidroside and low tyrosol contents. Angiotensin converting enzyme inhibitory activity seemed to change independent of tyrosol and salidroside contents with fermentation time.

These results indicate that Kefir culture-mediated fermentation of soymilk supplemented with Rhodiola extracts resulted in mobilization of total phenolics, which could be effectively designed as complimentary therapies for postprandial hyperglycemia linked to Type II diabetes management. Due to the significantly reduced α-amylase inhibitory activity at the end of fermentation, this approach would have minimal side effects such as abdominal distention, flatulence, meteorism and possibly diarrhea, which are caused by the excessive inhibition of pancreatic α-amylase by current drug therapies.     

Phenolic composition and functional properties of wild mint (Mentha longifolia var. calliantha (Stapf) Briq.)

Mints (Mentha species) are widely used as food, medicine, spice, and flavoring agents. At the present work, phenolics profile of infusion and ethanol extract of Mentha longifolia was determined using an RP–HPLC–DAD system. Total bioactive contents, radical scavenging, reducing power, metal chelating, and enzyme inhibitory activities relevant to Alzheimer’s disease, diabetes mellitus, and skin disorders were evaluated. Sixteen phenolic compounds (ten phenolic acids and six flavonoids) were identified in the extracts in which sinapic acid (7132 µg/g extract) and rosmarinic acid (6260 µg/g extract) were the most abundant compounds. Strong antioxidant effects were observed in 1,1-diphenyl-2-picrylhydrazyl radical, 2,2?-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), cupric ion reducing activity, ferric reducing antioxidant power, phosphomolybdenum, and metal chelating assays. Results indicated selective acetylcholinesterase inhibitory activity and high α-amylase and α-glucosidase inhibitory potential. Findings showed that M. longifolia has promising health benefits due to its high concentration of useful phenolic compounds and has great potential for possible applications in the preparation of functional ingredients.     

米曲霉优良菌株的筛选及在制曲发酵西瓜黄豆酱中的应用

为获得蛋白酶、淀粉酶活性优良的米曲霉菌株,采用牛津杯双层平板法初筛、制曲分析酶活性复筛的方法,从制酱用成品曲中获得1?株淀粉酶活性优良菌株CS3.04和1?株蛋白酶活性优良菌株CS3.22,结合形态特征,ITS?rRNA序列分析鉴定为米曲霉。将2?株米曲霉分别进行单一菌种制曲及混合菌种制曲发酵西瓜黄豆酱,与商业米曲霉菌株制曲发酵进行对比,结果显示：不同制曲方式发酵西瓜黄豆酱的理化指标变化趋势保持一致,混合菌种制曲发酵样品的还原糖及氨态氮含量最高,分别为107.37、6.76?g/kg,比接种商业米曲霉菌株制曲发酵的样品分别提高了11.02%、5.56%;采用液液萃取-气相色谱-质谱联用技术定性及定量分析西瓜黄豆酱的挥发性风味物质,发现混合菌种制曲发酵具有产醛类、醇类、酮类及短链酯类物质的优势,而接种CS3.04单一菌种制曲发酵更有利于产酸类及酚类物质;混合菌种制曲发酵样品整体感官评分优于单一菌种制曲发酵,且在香气与滋味上占有优势。混合菌种制曲发酵工艺因CS3.04和CS3.22的酶系互补作用,有效地提升了西瓜黄豆酱的品质。     

Oxidative Stability of Lipids Rich in EPA and DHA Extracted from Fermented Scallop Ovary

A novel seafood paste was developed by the fermentation of scallop ovary using rice malt (koji) and yeast culture. Chemical analysis of the product showed the formation of high level of free amino acids and organic acids during the fermentation. The product color and flavor resembled to Japanese traditional soybean miso. The contents of total lipids (TLs) extracted from the fermented products were ranged from 9.18% to 11.59% or 11.38% to 13.57%/dry sample weight. Although the TL was rich in oxidatively unstable polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), little decrease was found in these PUFAs during the fermentation, showing the high oxidative stability of the TL from the fermented scallop ovary. Moreover, the oxidative stability of the TL extracted from the fermented products increased with increasing the fermentation time. This would be mainly due to the formation of lipid soluble antioxidants such as tocopherols, which might be derived from yeast used for fermentation.     

Enhanced antioxidative activity of soybean koji prepared with various filamentous fungi

In the present study, soybean koji fermented with various GRAS filamentous fungi, including Aspergillus sojae BCRC 30103, Aspergillus oryzae BCRC 30222, Aspergillus awamori, Actinomucor taiwanensis and Rhizopus sp. These organisms are commonly used as starters in the fermentation of many traditional, oriental food products. The growth of starter organisms, total phenolic content, and antioxidative activities of the methanol extract of these kojis are compared with specific reference to alpha-diphenyl-2-picryl-hydrozyl (DPPH) radicals scavenging effects, Fe2+-chelating ability, and reducing power. Depending on starter organism, various extents of mycelia propagation (35.23-86.29 mg/g koji) were noted after 3 days of fermentation. Total phenolic content increased in soybean after fermentation. Koji also displayed enhanced antioxidative activates in comparison with the non-fermented soybean. Among the five kinds of koji tested, those fermented with Asp. awamori exhibited the highest levels of DPPH-free radicals scavenging activity, Fe2+-chelating ability and reducing power. The DPPH-free radicals scavenging activity and Fe2+-chelating ability of this soybean koji was ca. 8.9 and 6.7 fold that of the control. Analysis of the dose-response effect also revealed that before reaching a threshold point, there is a linear relationship between increases in antioxidative activity and increases in the concentration of the koji extract. These results show the potential for developing a healthy food supplement with soybean fermented by the GRAS filamentous fungi.     

Effect of meat washing on the development of impact odorants in fish miso prepared from spotted mackerel

BACKGROUND: Miso, a fermented soybean paste prepared using koji (rice malt inoculated with Aspergillus oryzae) has been commonly used as a traditional seasoning for several centuries in East Asian countries. A miso‐like fermented product was prepared using washed and unwashed meats of spotted mackerel (Scomber australasicus) with improved food functionality and aroma attributes. The evolution of aroma‐active volatiles was further evaluated during the early stages of maturation. RESULTS: The newly developed fermented product was rich in flavor. The product was found to contain 98 volatile compounds, including aldehydes, alcohols, esters, ketones, furans, sulfur‐ and nitrogen‐containing compounds, aromatics, and acids. Koji enzymes efficiently hydrolyzed protein and carbohydrate substrates in both the unwashed and washed fish meats. Significantly higher enzyme activities were observed when the unwashed meat was used as a raw material rather than when washed meat was used. The substrate specificity of koji enzymes plays an important role in the formation of volatile compounds. CONCLUSION: The results confirmed that meat washing can reduce the levels of certain aldehydes, ketones, and nitrogen‐containing compounds, and can thereby provide a pleasant aroma by reducing fishy odor in the finished product. Copyright © 2010 Society of Chemical Industry     

解淀粉芽孢杆菌SWJS22和米曲霉混合制曲在酱油发酵中的应用

以解淀粉芽孢杆菌SWJS22和米曲霉为发酵菌株,考察米曲霉单独制曲发酵、米曲酶和解淀粉芽孢杆菌曲料混合发酵以及双菌种混合制曲发酵对酱油理化指标及风味的影响。结果表明:曲料混合发酵的酱油氨基酸转化率有较大提高,色率和色深物质均低于米曲霉单独制曲发酵的酱油和双菌种混合制曲发酵的酱油,曲料混合发酵酱油和双菌种混合制曲发酵的酱油谷氨酸含量有明显提高。采用气相色谱-质谱对比分析3种不同曲料发酵酱油的风味物质,结果表明:3种酱油的风味物质种类差别不明显,重要风味成分在3种酱油中均有检出,曲料混合发酵的酱油酸类物质的含量最低。     

乳酸菌发酵对刺五加叶活性成分、体外抗氧化作用与降血糖相关酶的影响

为了对刺五加叶在益生菌发酵保健品领域的应用提供理论基础,以刺五加叶为原料,采用嗜酸乳杆菌、干酪乳杆菌、植物乳杆菌3种乳酸菌进行发酵,对发酵前后刺五加叶中活性成分含量变化进行研究,并评价刺五加叶乳酸菌发酵物的体外抗氧化作用与对降血糖相关酶的影响.结果表明:不同菌种的发酵能力存在差异,植物乳杆菌、嗜酸乳杆菌发酵显著增加了刺...