微细化处理对食用菌五谷面条蒸煮及质构特性的影响

研究微细化处理食用菌五谷面粉对其面条蒸煮及质构的影响,采用微粉碎技术对食用菌五谷混合粉进行处理,并对食用菌五谷面条蒸煮特性、质构特性、表面微观结构等进行检测。结果表明最佳物料粒度为160目(0.097 mm),其体积等效粒径为70.5μm。微细化处理后的混合粉粒径主要分布在3~40μm和40~500μm两个区间内,微细化处理后食用菌五谷面条的最佳蒸煮时间为(13.45±0.26)min;复水率、干物质吸水率分别增加到(93.20±2.28)%、(128.63±2.57)%,干物质损失率、熟断条率分别降低为(6.72±0.09)%、(5.00±0.32)%。质地剖面分析(texture profile analysis,TPA)实验结果表明面条延展性为(-4.09±0.10)g/s,硬度、黏性分别降低至(310.39±7.39)g、(-4.87±0.65)g·s,咀嚼性增加到(102.14±3.31)g·s;拉伸实验结果表明160目(0.097 mm)食用菌五谷面条拉断力最大,为(19.43±0.18)N,拉伸距离为(53.90±0.87)mm。扫描电子显微镜观察结果表明,随着微细化程度增加,面条表观改善,结构变得更加致密光滑,孔隙相对减少,有利于提高食用菌五谷面条的蒸煮耐性,改善其质构持性。     

草菇的化学特性与药理作用及保鲜与加工研究进展

对草菇的化学特性与药理作用及其保鲜与加工技术进展进行综述,分析草菇产业面临的关键技术问题并提出研究方向。草菇为高温菇,不耐储藏。草菇含有丰富的膳食纤维、蛋白质、氨基酸等营养成分,还含有葡聚糖、甾醇类化合物等功能成分,具有抗氧化、调节免疫、抗肿瘤等活性。主要的保鲜方式有冷藏保鲜、气调保 鲜、辐照保鲜、化学保鲜等。目前草菇的加工还处于粗浅阶段,急需发展深加工技术。     

Chemical Composition and Effect of Processing and Flour Particle Size on Physicochemical and Organoleptic Properties of Cocoyam (Colocasia esculenta var. esculenta) Flour

This work investigated the chemical composition of cocoyam corms and cormels and the effect of processing and particle size on the physicochemical and organoleptic properties of the flours for use as soup thickener. Fresh cocoyam corms and cormels were peeled, sliced, washed, divided into four parts that were variously blanched, sulphited and sulphited/blanched. The control was not treated. The slices were sun dried (32 ± 2°C, 3 days), milled and classified with standard sieves into particle sizes of 0.1, 0.2, 0.4, 0.6 mm. The flour samples and fresh corms and cormels were analyzed for the proximate composition, ascorbic acid, anthocyanin and oxalic acid contents. The flours were also analyzed for the pH, bulk density, water and oil absorption capacities and the sensory properties of colour and texture. On dry weight basis, the protein, fat, crude fibre, ash and carbohydrate contents of the corms, cormels and flours were the same (p > 0.05). Ascorbic acid, anthocyanin and oxalic acid contents were respectively reduced from averages of 30.35, 31.58 and 173.88 mg/ 100 g (dry weight) in the corm/cormel to ranges of 8.95 — 16.28, 9.58 — 15.90 and 141.69 — 160.68 mg/ 100 g in the flours. Bulk density was increased (p < 0.05) by blanching and particle size. The water and oil absorption capacities were increased (p < 0.05) by blanching. Colour preference was improved by sulphiting, blanching and decreasing particle size. Texture preference was only affected by particle size. Acceptablility of soups from flours were not affected by treatments and particle sizes.     

不同加工工艺对“云抗10号”滇红工夫茶品质影响

为提高滇红工夫茶的品质特征,以云南大叶种茶树“云抗10号”鲜叶为原料,按滇红工夫茶的加工工艺,调整萎调、揉捻、发酵和干燥4个工序,制得10个滇红工夫茶样,并对茶样进行感官审评和内含成分测定。结果表明,所制茶样的水浸出物含量为38.12%～45.35%,游离氨基酸含量为3.59%～5.53%、茶多酚含量为19.67%～26.45%,茶黄素含量为0.06%～0.09%,茶红素含量为1.66%～4.30%、茶褐素含量为3.71%～4.83%。滇红工夫茶的品质是各个加工工艺互相作用的结果,以重萎凋8 h～12 h,揉捻28 min～30 min,发酵12 h～14 h,干燥温度先高温(110℃～115℃)烘干1 h后低温(80℃～85℃)烘干1 h的加工工艺制得的“云抗10号”工夫红茶综合品质最佳。综上,研究结果对提升滇红工夫茶品质提供了理论依据。     

加工工艺对绿茶关键呈香成分的影响

以龙井43茶树品种的一芽二叶鲜叶为原料,按照传统工艺分别加工成炒青、烘青、蒸青、晒青4类绿茶,继而采用搅拌棒吸附萃取结合气相色谱-嗅闻-质谱技术研究分析了加工工艺对绿茶关键呈香成分的影响。结果表明：从炒青绿茶、烘青绿茶、蒸青绿茶、晒青绿茶样品中分别鉴定出了31、27、25、30种关键呈香成分,均以表现出花香、果香、青气特征的香气化合物为主;其中13种香气成分是4类绿茶共有的关键呈香成分,包括β-紫罗酮、萘、芳樟醇、芳樟醇氧化物I、香叶醇、1-辛烯-3-醇、2-庚酮、庚醛、己醛、乙酸叶醇酯、(E,E)-2,4-癸二烯醛、α-紫罗酮、苯乙醇。此外,研究表明,β-罗勒烯和(Z)-3-己烯基-α-甲基丁酸酯对炒青绿茶的香气品质有重要贡献,2-戊基呋喃、苯乙醛和α-松油醇对烘青绿茶的香气品质有重要贡献,而香叶基丙酮、γ-松油烯和α-柠檬醛对晒青绿茶的香气品质有重要贡献。研究结果有助于为揭示绿茶香气品质形成机理和研发绿茶香气品质定向加工调控技术提供参考依据。     

Effect of Maitake (Grifola frondosa) Mushroom Powder on Bread Properties

ABSTRACT: Maitake mushroom powder drastically decreased dough strength in Brabender farinography and was also effective in deteriorating bread-making properties (bread height and specific volume). These effects of maitake on farinograph values and bread-making properties were lost by boiling maitake/water suspensions or by adding EDTA, suggesting that the deteriorative effects by maitake may be caused by a metal protease. Flour dough that contained maitake was treated with 1% sodium dodecyl sulfate (SDS), and extracted proteins were subjected to SE-HPLC and SDS-PAGE. The range of high-molecular-weight (HMW) protein in those profiles gradually decreased with an increase of maitake, and HMW protein/total protein correlated well with bread height but did not have a clear effect on specific volume.     

Effects of Gamma Irradiation on the Chemical Composition and Antioxidant Activity of Lactarius deliciosus L. Wild Edible Mushroom

The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. There has been extensive research on finding the most appropriate technology for mushrooms preservation and a particular interest arises for wild species. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. Herein, the effects of gamma irradiation on Lactarius deliciosus (L. ex Fr.) S. F. Gray chemical composition and antioxidant activity were evaluated in samples submitted to different storage periods (0, 4 and 8 days) at 4 °C. The irradiation treatments were performed in a Co-60 experimental equipment. Nutritional value was accessed by macronutrients analysis and determination of energetic value; fatty acid, sugar and tocopherol profiles were determined by gas chromatography–flame ionization detector, high-performance liquid chromatography (HPLC) refractive index and HPLC fluorescence, respectively. The antioxidant activity was evaluated through radical scavenging activity, reducing power, lipid peroxidation inhibition and phenolics content. The obtained data show that, until 1 kGy, gamma irradiation might provide a useful alternative to ensure the quality and extend the life of mushrooms, since its effects on macronutrients, energetic value, tocopherols and antioxidant activity EC₅₀ values were less significant than the changes caused by storage time. Moreover, the chemical and nutritional composition was similar in irradiated and non-irradiated L. deliciosus samples.     

Injection‐Salting and Cold‐Smoking of Farmed Atlantic Cod (Gadus morhua L.) and Atlantic Salmon (Salmo salar L.) at Different Stages of Rigor Mortis: Effect on Physical Properties

ABSTRACT: Processing of fish is generally conducted postrigor, but prerigor processing is associated with some potential advantages. The aim of this study was to study how 5 processing regimes of cold‐smoked cod and salmon conducted at different stages of rigor influenced yield, fillet shrinkage, and gaping. Farmed cod and salmon was filleted, salted by brine injection of 25% NaCl, and smoked for 2 h at different stages of rigor. Filleting and salting prerigor resulted in increased fillet shrinkage and less increase in weight during brine injection, which in turn was correlated to the salt content of the fillet. These effects were more pronounced in cod fillets when compared to salmon. Early processing reduced fillet gaping and fillets were evaluated as having a firmer texture. In a follow‐up trial with cod, shrinkage and weight gain during injection was studied as an effect of processing time postmortem. No changes in weight gain were observed for fillets salted the first 24 h postmortem; however, by delaying the processing 12 h postmortem, the high and rapid shrinking of cod fillets during brine injection was halved.     

加工处理方式对冲菜中硫代葡萄糖苷的影响

采用高效液相色谱法,对冲菜中主要的硫代葡萄糖苷种类和含量进行分析,并选择微波、热烫和蒸汽3种方法对冲菜进行处理,研究冲菜中硫代葡萄糖苷在不同处理过程中的热降解情况。结果表明：冲菜中含有两类硫代葡萄糖苷：脂肪族和吲哚族硫苷,其中含量较高的3种硫代葡萄糖苷分别为progoitrin、glucobrassicin和4-methoxyglucobrassicin;硫代葡萄糖苷在微波、热烫和蒸汽3种处理过程中的热降解均符合一级热降解动力学模型,其中glucotropaeolin的热稳定性均最差;对冲菜中总硫代葡萄糖苷的降解作用从大到小的顺序依次为：蒸汽、热烫、微波,但是微波处理最能促使对十字花科蔬菜中风味贡献最大的脂肪族硫苷的降解。     

不同工艺条件对卤牛肉中脂肪酸含量影响的研究

通过气相色谱法对对照组和试验组卤牛肉样品中的脂肪酸含量进行测定分析,通过结果分析得出,试验组比对照组中的亚油酸和豆蔻酸含量分别降低了76.35%和4.33%;而其中的软脂酸、硬脂酸、油酸含量分别增加了17.05%,51.53%和84.78%。     

Processing Effects on Chemical,Functional and Pasting Properties of Cowpea Flour from Different Varieties

Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea.     

不同化学处理对碳纤维分散及成纸性能的影响

通过联合Zeta电位、吸光度和数码图像分析,考察了碱性预处理和不同试剂表面处理对碳纤维分散性的影响,并以碳纤维配加纸浆制取纸样,检测纸张的物理强度和体积电阻率。实验结果表明:碱性预处理可改善碳纤维分散性,吐温-80和CPAM试剂都可显著提高碳纤维分散性及成纸抗张指数和电导率,但作用机理截然不同。吐温-80通过降低固液表面张力,提高水对纤维的润湿能力,改善碳纤维分散性;CPAM则是通过形成三维空间大网络絮体,阻止碳纤维的运动聚集,来改善其在纸浆中的分散。     

Tuning the Functional Properties of Polysaccharide–Protein Bio‐Based Edible Films by Chemical,Enzymatic, and Physical Cross‐Linking

Among natural biopolymers, polysaccharides and proteins are very promising for biodegradable and edible wraps with different characteristics, so that their formulations can be tailor‐made to suit the needs of a specific commodity. Films prepared from polysaccharides have good gas barrier properties but exhibit lower resistance to moisture compared to protein films (edible) or polylactide films (biodegradable). Protein‐based films show better mechanical and oxygen barrier properties compared to polysaccharide films. For that reason, film performances may be enhanced by producing blend systems, where hydrocolloids (mixtures of proteins and/or polysaccharides) form a continuous and more cohesive network. However, the lower water barrier properties of hydrocolloid films and their lower mechanical strength in comparison with synthetic polymers limit their applications in food packaging. Therefore, the enhancement of biopolymer film properties has been studied to attain appropriate applications. This review provides an extensive synthesis of the improvement of the properties of edible polysaccharide–protein films by way of various chemical, enzymatic, and physical methods. These methods primarily aim at improving the mechanical resistance. They also permit to ameliorate the water and gas barrier properties and related functional properties.     

不同工艺条件对卤牛肉中挥发性风味物质影响的研究

本研究采用SDE与GC-MS法对不同工艺条件下的卤牛肉中的挥发性风味物质成分进行测定与分析,结果表明,试验组共测出44种挥发性物质,少于对照组中测出的51种挥发性物质,通过成分的分析,为以后的工艺与风味研究提供一定的依据。     

Chemical Composition and In Vitro Polysaccharide Fermentation of Different Beans (Phaseolus vulgaris L.)

ABSTRACT:  The composition of bioactives including polysaccharide yield and resistant starch (RS) content of 4 raw and cooked bean ( Phaseolus vulgaris  L.) cultivars was evaluated. Polysaccharide was fermented  in vitro  by incubation with human gut flora under anaerobic conditions and short-chain fatty acids (SCFAs) production was compared at 6, 12, and 24 h by gas chromatography. Polysaccharide and soluble fiber contents increased upon cooking with stachyose as the major oligosaccharide. Cooked bean of cultivar Bayo Madero had the highest yield of polysaccharides (55%) and resistant starch (37%), followed by those of Negro 8025 (48% and 32%, respectively). Acetate was the most abundant SCFAs formed in all bean varieties. The concentration of SCFAs was cultivar-dependent; Bayo Madero and Negro 8025 displayed the highest concentration of butyrate (15 mmol/L), while Azufrado Higuera had the lowest and highest concentrations of acetate (39 mmol/L) and propionate (14 mmol/L), respectively. The results suggest that the common bean is an excellent source of polysaccharides that can be fermented in the colon and produce SCFAs, compounds previously reported to exert health benefits.