发酵温度对南极磷虾虾酱流变特性和风味品质的影响

研究发酵温度（15、25 ℃和35 ℃）对南极磷虾虾酱静态和动态流变性质及风味品质的影响。结果表明, 南极磷虾虾酱是一种剪切变稀的非牛顿流体,具有弱凝胶特性。随着发酵温度的升高和时间的延长,样品的凝胶特 性减弱,35 ℃对虾酱凝胶结构的弱化作用最显著。25 ℃发酵能提高虾酱的凝胶稳定性,发酵至9 d时样品的表观黏 度、储能模量和损耗模量均达到最大。利用顶空固相微萃取-气相色谱-质谱联用技术在3 个温度发酵虾酱中分别分 离鉴定出39、41、37 种挥发性风味物质,其中（E,E）-2,4-庚二烯醛、壬醛、癸醛、苯甲醛和苯并噻唑在3 种虾酱中 均被检出,为南极磷虾虾酱的主体风味成分;25 ℃发酵虾酱中还鉴定出3-乙基-2,5,-二甲基吡嗪和2,3,5-三甲基-6-乙 基吡嗪,其增强了虾酱的风味;35 ℃发酵虾酱中则检出产生腥臭味的成分三甲胺。结合感官评价,25 ℃发酵 9～12 d的南极磷虾虾酱具有最佳的流变特性和风味品质。     

Selected Physicochemical Properties of Starch Isolated from Fermented Sorghum Flour

Starch was isolated from fermented sorghum flour (24 h natural lactic acid fermentation), and water retention, starch solubility, clarity of starch pastes and freeze‐thaw stability were measured. In comparison with starch isolated from unfermented sorghum flour, fermentation increased the solubility of the starch and decreased the water retention, but it had no effect on the freeze‐thaw stability of the starch. There was no substantial difference in the starch paste clarity between the two samples. Storage of starch pastes at lower temperature (4°C) resulted in a very low clarity of starch.     

Effect of saponins on the foam/flow properties of paste and physical characteristics of akara made from decorticated black‐eyed cowpeas

Akara, a deep‐fat‐fried cowpea paste product, is a popular snack food in West Africa. Foaming capacity of the cowpea paste is important for achieving a spongy light‐textured fried product. The effect of two saponins, Yucca and Quillaja, on the foaming capacity of cowpea paste was investigated. Results showed that an increase in the amount of saponin added (1, 2, 4%) resulted in a decrease in specific gravity and apparent viscosity of the cowpea paste. Addition of saponin also significantly reduced the firmness and increased the cohesiveness of the akara compared with the control. Akara made using the Quillaja saponin was less firm and more cohesive than akara made using the Yucca saponin. An increase in the amount of saponin added to the cowpea paste resulted in a darker (lower L*) and browner colour of akara. However, akara containing 1% Yucca saponin had similar colour attributes to the control but was less firm and more cohesive. Copyright © 2005 Society of Chemical Industry     

Development of ready‐to‐eat rice starch‐based puffed products by coupling freeze‐drying and microwave

The rice starch mixtures with varying amylose contents (AC) of 0.12–19.00% weight were prepared by mixing waxy and nonwaxy rice starches. The 5% rice bran oil shortening was added in the starch paste. After gelatinisation, thin slabs of starch pastes were aged at 4 °C for 24 h. The aged slabs were dried by freeze‐drying to obtain 25% moisture content. A microwave oven set to 600 J s^?1 for 90 s was then used for puffing. The crucial factors affecting the snack purchase were texture and nutrition. The relative crystallinity and retrogradation enthalpy (?H_r) of freeze‐dried pellets increased with increasing the AC. From using a differential scanning calorimeter (DSC), endotherms of pellets were shown only when AC > 0.12%. An amylose–lipid complex was shown in pellets with AC ≥ 9.00%. Relationships between the AC and all puffed product properties were linear. Increasing AC provided greater hardness, fracturability, bulk density, but lower expansion ratio. From the sensory evaluation, the panellists preferred the puffed products with 9.00% AC. Increasing the AC gave higher crispness, hardness, brittleness, air cell opacity and density, but resulted in less puffiness. Thus, the microwave drying has the potential to puff a healthy expanded snack but giving the desirable properties depends on AC.     

Next‐Generation Sequencing Analyses of Bacterial Community Structures in Soybean Pastes Produced in Northeast China

Fermented soybean foods contain nutritional components including easily digestible peptides, cholesterol‐free oils, minerals, and vitamins. Various fermented soybean foods have been developed and are consumed as flavoring condiments in Asian regions. While the quality of fermented soybean foods is largely affected by microorganisms that participate in the fermentation process, our knowledge about the microorganisms in soybean pastes manufactured in Northeast China is limited. The current study used a culture‐independent barcoded pyrosequencing method targeting hypervariable V1/V2 regions of the 16S rRNA gene to evaluate Korean doenjang and soybean pastes prepared by the Hun Chinese (SPHC) and Korean minority (SPKM) populations in Northeast China. In total, 63399 high‐quality sequences were derived from 16 soybean paste samples collected in Northeast China. Each bacterial species‐level taxon of SPHC, SPKM, and Korean doenjang was clustered separately. Each paste contained representative bacterial species that could be distinguished from each other: Bacillus subtilis in SPKM, Tetragenococcus halophilus in SPHC, and Enterococcus durans in Korean doenjang. This is the 1st massive sequencing‐based study analyzing microbial communities in soybean pastes manufactured in Northeast China, compared to Korean doenjang. Our results clearly showed that each soybean paste contained unique microbial communities that varied depending on the manufacturing process and location.     

Studies concerning the use of <Emphasis Type="Italic">Lactobacillus helveticus</Emphasis> and <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis> for rye sourdough fermentation

The aim of this study was to investigate the fermentation behaviour, antioxidant activity and rheological behaviour of the sourdoughs prepared with Lactobacillus helveticus and Kluyveromyces marxianus. The final acidity of the sourdough after 18 h of fermentation was higher at higher temperatures (40 °C) and for the formulations with whole rye flour. The highest lactic/acetic acid ratios were obtained in case of more fluid sourdoughs fermented at 40 °C. The antioxidant properties of the sourdoughs are correlated with metabolic activity of the microorganisms, the DPPH radical scavenging activity being higher for optimum conditions of Lactobacillus helveticus growth. On the other hand, the rheological properties of the sourdoughs are not significantly influenced by the temperature. Sourdoughs formulations with whole flour are more viscous, as well as the controls fermented by the spontaneous microflora. The results of the bread-making process simulation by means of Mixolab indicate differences between dough formulations mainly depending on flour type.     

甲基纤维素对面糊流变性能及油炸挂糊肉片油脂渗透的影响

为增强油炸挂糊食品外裹糊稳定性以及降其含油率,本研究以甲基纤维素（MC）为研究对象,通过在面糊中加入0.4%~1.2%的甲基纤维素,探讨其对面糊流变性能、热特性及油炸挂糊肉片脂肪含量的影响。结果表明:随着MC添加量的增加,面糊的挂糊率和黏度不断上升,面糊黏弹性凝胶形成速度加快,同时热稳定性得到提高。添加MC可以有效地降低油炸挂糊肉片的脂肪含量,且当添加量为1%时,外壳与肉的脂肪含量最低分别为14.29%和3.05%,与对照组相比分别降低了61.06%和31.15%,苏丹红染色区域最小,油脂渗透深度最低为0.08 mm,其抑油效果最佳。因此,甲基纤维素能有效地改善面糊的流变性能以及降低油炸挂糊食品的脂肪含量。     

香菇柄发酵酱营养品质及风味成分研究

该研究在传统发酵酱的基础上,添加香菇柄粉制备香菇柄发酵酱,并对其进行水分、还原糖、氨基酸态氮、红色指数及氨基酸等指标测定,采用气相色谱-离子迁移谱联用（GC-IMS）技术分析其挥发性风味成分。结果表明,香菇柄发酵酱中还原糖含量（21.12%）及红色指数（1.44）均明显高于传统发酵酱,其水分含量（62.79%）及氨基酸态氮含量（0.76%）稍低于传统发酵酱。两种发酵酱中均测出17种氨基酸（包含7种必需氨基酸）,传统发酵酱、香菇柄发酵酱氨基酸总量分别为99.09 mg/g、87.71 mg/g,且两种发酵酱中呈味氨基酸比例相似。两种发酵酱均共检测出32种挥发性成分,包括醇类8种、醛类9种、酯类3种、酮类4种、酸类3种、吡嗪类2种、呋喃类2种、醚类1种。研究表明,香菇柄发酵酱品质符合国标GB 2718—2014《酿造酱》的要求。     

Rheological and Textural Characteristics of Date Paste

The rheological properties of two commercial date pastes were investigated in the temperature range of 20–70°C. From typical flow behavior curves, it was observed that date pastes exhibited pseudoplastic behavior. The shear stress-shear rate data were fitted using six common rheological models. The Casson model best described the experimental data at all temperatures. The Arrhenius model described successfully the temperature dependence of apparent viscosity of date pastes (R² > 0.99) with an E_a value in the range of 25,392.6–25,485.7 kJ/kmol. The textural attributes measured were: hardness, springiness, gumminess, cohesiveness, chewiness, and adhesiveness for the texture profile analysis test, and firmness, adhesive force, mean load, and total positive area for the Ottawa test. There was a significant difference in textural attributes between two varieties of date paste studied. Texture profile analysis results showed that all parameters obtained for black date pastes were higher than golden date pastes except for springiness and cohesiveness. However, the Ottawa results showed that golden date pastes were firmer and less adhesive than black date pastes.     

Rheological properties of pullulan fermentation broth in a stirred tank fermentor

Abstract

The rheological properties of the fermentation broth during pullulan production from synthetic medium by Aureobasidium pullulans P56 in a stirred tank fermentor were investigated. The mycelial forms and the production of extracellular polysaccharide were responsible for the non‐newtonian flow behaviour of the fermentation broth. The rheological behaviour can be characterized by a power law type of equation. The relationship shear rate/shear stress and shear rate/apparent viscosity showed a non‐newtonian behaviour of the fermentation broth. The power law index was found to be a sensitive factor for the indication of the pseudoplastic behaviour of the broth.     

Functional Properties of Cowpea Paste as Influenced by Indigenous Microflora

The influence of indigenous microorganisms on several functional properties of cowpea (Vigna unguiculata) paste was investigated. Six formulas [with and without onion, salt and pepper; inoculated (indigenous microflora) and uninoculated] were prepared and incubated for 24 hr at 30°C. Lactic acid bacterial populations were similar to total aerobic microbial populations which increased with time of incubation. Pastes containing salt were associated with high equilibrium moisture contents. As incubation time progressed, pH and emulsion capacity decreased and specific gravity and apparent viscosity increased, while oil and water binding capacity remained unchanged. Formula content and incubation time did not influence the color of cowpea pastes; however, akara, a deep-fat fried product prepared from the paste, did have a darker color when made from paste which had been incubated for 24 hr.     

The influence of douchi starter cultures on the composition of extractive components, microbiological activity, and sensory properties of fermented fish pastes

Three experiments were conducted to test the hypothesis that douchi cultures could serve as a potential starter for enhancing the quality attributes of fermented silver carp meat. In experiment 1, an active, prefermented douchi culture was incorporated into a fish paste to aid in the fish fermentation (30 d) and facilitate biochemical production of extractive flavor components (PRF). In experiment 2, a fully fermented (30 d) douchi was added to a fish paste and the mixture was fermented for 30 d (PSF). In experiment 3, a fish paste without the douchi culture was fermented for 30 d (CF). Total extracted free amino acids increased by 68.0, 68.6, and 78.8% (P < 0.05) from their initial levels to 2930, 2422, and 1573 mg/mL after 30 d of fermentation for PRF, PSF, and CF fish pastes, respectively, of which, glutamic acid, aspartic acid, alanine, lysine, and leucine were the major amino acids (>100 mg/mL). The concentrations of both formaldehyde-reactive nitrogen and ammonia nitrogen extractives increased significantly (P < 0.05) during fermentation, following the order of PRF > PSF > CF. Low amounts of biogenic amines (<25 ppm) were produced in all samples. Sensory panel evaluation showed that PRF fish pastes had desirable aroma and taste. The douchi-inoculated fermentation could be a novel technique for expanding the utilization, consumption, and the economic values of silver carp meats. Practical Application: Douchi, a fermented soybean product, is a traditional food flavoring ingredient commonly used in China, Japan, and other Asian countries. It is also used in many Chinese cuisines in the United States. On the other hand, fermented seafood made from freshwater fish such as silver carp is known to contain bioactive components believed to promote health. The findings from the present study indicated that douchi as a novel starter can be used to produce fermented silver carp fish pastes with excellent flavor and consumer acceptability. The results may be applicable to other fish species to produce similar fermentation products.     

Enhancement of the antioxidant and starch hydrolase inhibitory activities of king coconut water (Cocos nucifera var. aurantiaca) by fermentation with kombucha ‘tea fungus’

Enhancement of antioxidant and starch hydrolase inhibitory properties of king coconut water when subjected to fermentation with the ‘tea fungus’ was evaluated. pH, colour, viscosity, ethanol content, antioxidant activity, total phenolic content, ferulic and p‐coumaric acid contents and starch hydrolase inhibitory activities were analysed for 7 days in fermented and unfermented king coconut water samples. The fermented sample had a statistically significant decrease (P < 0.05) in pH. Colour values indicated the fermented beverage to increase in ‘yellowness’ over time. A statistically significant increase in the total phenolic content and the antioxidant activity (P < 0.05) was observed from day 1 onwards in the fermented sample. The starch hydrolase inhibitory activities in the fermented beverage had statistically significantly increased (P < 0.05) by day 7. Overall, the study highlights an enhancement of the antioxidant and starch hydrolase inhibitory properties of king coconut water as a result of the kombucha‐based fermentation.     

Steady and Dynamic Shear Rheology of Fucoidan‐Buckwheat Starch Mixtures

Rheological properties of fucoidan (F) and buckwheat starch (B) mixtures (3% or 6%) at different blending ratios of fucoidans (0, 0.1, 0.2, 0.5 and 1.0%) were investigated in steady and dynamic shear. Steady shear viscosity measurement revealed that aqueous pastes of the BF blends (3%, w/v) had a pseudoplastic and shear‐thinning behavior with flow behavior index (n) values of 0.61–0.68. The substitution of starch with fucoidan polymers significantly lowered the apparent viscosities compared with the pure starch paste and, when mixed with less than 0.5% of fucoidan, the viscosities of the pastes were even lower than those of the starch pastes at the corresponding starch concentrations. According to dynamic viscoelastic measurement performed at 6% total carbohydrate concentration, buckwheat starch mixtures behaved like weak gels and the BF blends containing less than 0.5% fucoidan had considerably lower storage (G') and loss (G') moduli than the starch paste at the corresponding starch concentrations. However, the magnitude of G' increased with fucoidan concentrations over 0.5%, suggesting that a concentration of fucoidans > 0.5% might enhance the formations of three‐dimensional networks and crosslinking of the starch samples, probably because of the mutual exclusion between starch and fucoidan polymers through the phase separation process. This study indicates that it is possible to obtain the BF blends having various rheological properties by changing the concentration of fucoidan polymers.     

Correlation of fatty acid composition of vegetable oils with rheological behaviour and oil uptake

The fatty acid compositions of seven edible vegetable oils were investigated and correlated with their rheological behaviours and the amount of absorbed oils to fried products. All oil samples showed constant viscosity as a function of shear rate, exhibiting Newtonian behaviours. The highest viscosity was observed in hazelnut oil, followed by olive, canola, corn, soybean, sunflower, and grapeseed oils. In addition, a high correlation (R² = 0.94) demonstrated that the flow behaviours of vegetable oils were positively governed by their major components (18:1 and 18:2 fatty acids). It was also shown that a more rapid change in viscosity with temperature was observed in the oils containing more double bonds (R² = 0.71). Furthermore, even though the overall tendency was that the potato strips fried in the oils with high viscosity appeared to cause more oil uptake, a significant effect of oil types on oil uptake was not observed.     

Effect of Holding Time on the Functionality of Cowpea Paste and Quality of Akara

Whipped cowpea pastes were held at room temperature (20°C) for 0, 30, 60, 120, and 240 min before preparation of akara (fried cowpea paste). Apparent viscosity of whipped paste was measured at different shear rates (0.17, 0.34, 0.85, 1.70, 3.40, 6.80, and 17.00 sec^?1). At any given shear rate, paste became more viscous with increasing holding time. Akara became darker and less yellow in color as paste holding time increased. Akara made from paste held 120 min or longer had an unacceptably dense, firm texture.     

不同菌种发酵制备蚕豆酱的研究

本试验研究米曲霉、黑曲霉、黑根霉、高大毛霉4种不同单一菌种分别发酵制得的蚕豆酱中蛋白酶、淀粉酶活力及主要成分、酱色OD420nm值等指标在不同发酵时期的变化,并对发酵42d的蚕豆酱进行感官评价。结果表明,米曲霉的中性及碱性蛋白酶活力较其他三种菌强,分别高达546.84U和188.79U。米曲霉发酵的蚕豆酱氨基酸态氮含量最高,可达1.381 g/100g,根霉、黑曲霉次之,毛霉最少。米曲霉和黑曲霉制得酱的颜色深,酱色OD420nm值高,另两种霉制得酱的颜色较浅。米曲霉发酵制得蚕豆酱在色泽、气味和口感上都达到一级标准,是制作蚕豆酱的良好发酵菌种。     

Influence of elephant apple powder as an adsorbent in the regeneration of fried soybean oil: Process optimization studies

In the present work, elephant apple powder (EAP) has been characterized as an adsorbent by analyzing its properties in Fourier transform infrared, scanning electron microscope, and Brunauer–Emmett–Teller surface analyser. Furthermore, the effect of EAP on the regeneration of fried soybean oil was studied by performing frying experiments with potato chips at 180 ± 5 °C for 5 hr/day in a deep fat fryer for 5 days. Oil samples were drawn periodically for evaluating the quality parameters (free fatty acid, peroxide value, iodine value, p‐anisidine value, and total polar content). The effect of process variables (contact time, heating time, and concentration of adsorbent) on the quality parameters of the fried oil was examined using response surface methodology. Results indicated that the process variables had a significant effect on the final quality of the oil. From the study, it was revealed that the quality of fried soybean oil has improved after treating with EAP.

Practical applications

The present work provides the useful information regarding the treatment of deep fried oil using a natural adsorbent. The method used in the work is cost‐effective and regenerates oil with good quality. The method of regeneration may be utilized by small and medium scale food processors as the process is simple. The results of this study showed that elephant apple powder can be used as an adsorbent to improve the quality parameters of deep fried soybean oil.     

Functional Property Changes in Partially Defatted Peanut Flour Caused by Fungal Fermentation and Heat Treatment

Changes in functional properties of flour made from partially defatted peanut fermented with Rhizopus microsponrus var. oligospoms and treated with steam were investigated. An ester-like aroma was detected in fresh fermented peanut and soy sauce or meat-like flavors were detected in dried fermented peanut. Nitrogen solubility (pH 4.0–6.0), emulsion capacity and viscosity. water adsorption, and water and oil retention of flours were slightly increased as a result of fermentation. Steam treatment of nonfermented and fermented peanut flours for up to 45 min enhanced some functional properties.     

自然发酵对糙米煎饼理化性质的影响

通过对自然发酵煎饼不同时期的常规营养成分、pH值、RVA特征值、色差、糊化度、剪切力等指标的测定,研究自然发酵的煎饼的营养成分、质构性质、老化性质、感官品质、保藏品质的变化规律。研究表明经过自然发酵的煎饼蛋白质含量增加,蛋白质和脂肪经过微生物的作用更加容易被人体吸收利用,提高了煎饼食品的营养价值;外观颜色更加丰富饱满,感官品质提高;发酵后的煎饼抗老化能力增加,保藏期间的质量得到改善。通过对煎饼糊发酵过程中的理化性质及煎饼质构性质的变化的研究,探讨其发酵机理,从而为发酵煎饼的工业化生产奠定基础。