金华火腿工艺过程蛋白质水解及其相关性研究

本文通过对金华火腿工艺过程总氮、非蛋白氮及游离氨基酸的分析研究,来确定其蛋白质分解与工艺过程产品水分、NaCl含量及温湿度条件的相关性;结果表明:工艺过程中非蛋白氮和游离氨基酸的变化与工艺过程湿度和产品水分的降低、温度和NaCl含量的提高呈正相关,且蛋白质在工艺过程中发生了持续降解。     

三川焐灰火腿和风干火腿发酵过程中理化性质变化

研究三川焐灰火腿和风干火腿发酵过程中理化性质的变化,分析发酵方式不同的2 种火腿在发酵6～12 个月期间主要理化性质,如pH值、水分含量、水分活度、总挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、NaCl含量、蛋白质含量、色差（亮度值（L*）和红度值（a*））及游离氨基酸含量的变化。结果表明：发酵6～12 个月期间,三川焐灰火腿的pH值由6.05升至6.13,风干火腿由6.02升至6.09,在发酵成熟过程中,焐灰火腿的pH值始终高于风干火腿;焐灰火腿的水分含量由54.2%降至43.0%,水分活度由0.71降至0.65,风干火腿的水分含量由50.3%降至41.4%,水分活度由0.69降至0.65;焐灰火腿的TVB-N含量由30.1 mg/100 g上升至65.1 mg/100 g,风干火腿由31.7 mg/100 g上升至60.9 mg/100 g;焐灰火腿的NaCl含量由4.48%上升至5.40%,风干火腿由4.60%上升至5.52%;焐灰火腿的蛋白质含量由28.8%上升至38.4%,风干火腿由30.2%上升至40.9%;焐灰火腿和风干火腿的色差值呈一系列复杂变化;焐灰火腿和风干火腿发酵过程中均检测出17 种游离氨基酸,各游离氨基酸含量变化趋势与游离氨基酸总含量相似,且各游离氨基酸含量在发酵过程中的变化有明显的差异性。     

三川火腿成熟过程中主要理化性质变化的研究

目的研究三川火腿成熟过程中主要理化性质的变化,以提高三川火腿的品质和改进加工技术。方法以传统工艺制作的三川火腿为原料,研究其8个月成熟过程中主要理化指标的变化,包括pH、水分、氯化钠、挥发性盐基氮、亚硝酸盐和游离氨基酸。结果三川火腿在成熟过程中pH值整体呈现弱酸性;水分含量持续下降至46.29%;氯化钠含量和挥发性盐基氮在发酵过程中不断上升至10.74%和70.54 mg/100 g;亚硝酸盐呈现出先稍降低后逐渐上升的趋势,最终含量为0.62 mg/kg;游离氨基酸总量先升后降,在8月达到最大值7.06%。结论弱酸性的生存环境、较低的水分含量、适宜的盐含量很好地抑制了腐败细菌在三川火腿上的生长;较低的亚硝酸盐含量保证了三川火腿的品质;适宜的挥发性盐基氮含量和游离氨基酸含量对三川火腿的风味具有重要影响。     

金华火腿发酵程度检测及产品品质评定

以金华火腿为研究对象,研究加工和贮藏周期对金华火腿水分、盐分和蛋白质水解指数的影响,以期建立金华火腿发酵程度指标。研究表明,水分和盐分含量不能完全区分金华火腿和一些其他产品(如全精腿等),且按照现行标准中水分和盐分要求评价火腿品质存在一定缺陷;蛋白质水解指数能够直观且快速的评价金华火腿的发酵程度,同时可以用来区分金华火腿和一些其他肉制品。蛋白质水解指数的检测是一种稳定、快速、经济的检测方法,可以用来表征金华火腿加工中蛋白质变化与发酵程度的关联性。通过抽样验证试验,确定金华火腿蛋白质水解率变化的量化指标(20%),为金华火腿制定发酵程度的标准提供参考。     

宣威火腿生产气候变化的研究

在参照历年气象资料基础上,研究了云南宣威火腿生产过程中的气候特征、湿度、温度变化以及在此气候条件下生产出来的宣威火腿的水分含量、盐分含量等参数变化情况.     

金华火腿调味料风味前体物质酶解制备工艺研究

金华火腿是我国传统的干腌肉制品,以其特有的风味著称.以金华火腿为原料,利用酶解技术获得金华火腿调味料风味前体物质——酶解液.并通过响应面分析方法优化酶解工艺.研究结果表明,优化的酶解工艺条件为料水比1/5、碱性蛋白酶用量2.10%、初始pH 8.60、酶解温度65℃、酶解时间3 h.在此条件下金华火腿的水解度为14.20%.所得水解液中氨基酸含量52.544 g/L,其中必需氨基酸含量12.859g/L.产品具有浓郁的金华火腿香味.     

金华火腿加工过程中的理化特性

以传统金华火腿为原料 ,跟踪测定了火腿加工全过程中半膜肌和股二头肌的水分、NaCl、非蛋白态氮 ,水溶性氮和游离氨基酸含量的变化情况。结果表明 ,半膜肌和股二头肌的水分含量逐渐降低 ;NaCl含量逐步上升 ,水溶性氮的含量在加工过程中先降低后升高 ,非蛋白态氮的含量也逐步上升。各种游离氨基酸随着加工的进行 ,含量逐渐增加 ,尤其是谷氨酸 ,金华火腿主要的鲜味物质 ,在加工过程中含量显著增加。     

宣恩火腿加工过程中理化指标变化的分析

为研究宣恩火腿加工过程中理化特性的变化规律,以宣恩火腿加工过程中原料(鲜腿)、腌制期、发酵初期、发酵中期、发酵末期、成品6个工艺点的火腿为原料,检测其股二头肌中水分、灰分、pH值、总氮、水溶性氮、非蛋白氮等指标变化情况,并对其游离氨基酸的组成和含量分析以及呈味肽的电子舌评价。结果表明:在宣恩火腿加工过程中,股二头肌的水分含量持续下降,灰分含量持续上升,而pH值则一直较稳定;总氮含量先下降再上升;水溶性氮含量先上升,从发酵末期开始稍有下降;非蛋白氮含量先持续升高,从发酵中期开始下降;呈味氨基酸在腌制期和发酵中/后期大量生成;火腿的酸味、苦味、涩味总体上不断减小,而鲜味、浓厚味和咸味这些较好的风味不断增加。     

湖北宣恩火腿基本成分分析

以湖北宣恩火腿为原料,测定其股二头肌部位的水分、蛋白质、脂肪、氨基酸、脂肪酸等含量。结果表明:宣恩火腿营养丰富,基本成分含量:水分55.18%、蛋白质22.80%、脂肪21.55%,pH 6.35;宣恩火腿中被检测出的氨基酸17种,必需氨基酸7种,占总氨基酸含量的29.47%;非必需氨基酸10种,占总氨基酸含量的70.53%;含量较高的游离氨基酸有Ala、Pro、Leu、Val、Ile和Phe;含量较高的脂肪酸有棕榈酸(C16∶0)、油酸(C18∶1)和亚油酸(C18∶2)。     

火腿风味的低钠发酵肉制品品质及风味研究

以猪后腿肉为原料,利用发酵火腿生产工艺参数制成具有火腿风味的产品。采用乳酸钾和L-精氨酸替代30%钠盐用于加工,研究其对发酵肉制品水分活度、颜色、水分含量、蛋白质含量、质构特性、硫代巴比妥酸值等品质指标及产品风味的影响。结果表明:采用不同配比的乳酸钾和L-精氨酸替代30%的钠盐,在保证产品风味的同时,均能降低发酵肉制品中钠含量;结合理化指标及感官评定,采用9%L-精氨酸+21%乳酸钾或12%L-精氨酸+18%乳酸钾的效果最佳。     

CHEMICAL AND ANTIOXIDANT PROPERTIES OF CULTIVATED AND WILD FRAGARIA AND RUBUS BERRIES

ABSTRACT

Content of individual sugars, organic acids, total phenolics (TPH), some important phenolic compounds (kaempferol, myricetin, quercetin, and ellagic acid) and total antioxidant capacity (TAC) in the fruits of strawberry, raspberry and blackberry were studied. A comparison was made between cultivars and wild relatives of each species (Fragaria vesca L., Rubus idaeus L. and Rubus fruticosus L.). The main sugars found were fructose and glucose both in the fruits of wild species and the studied cultivars. Citric acid was determined to be the major organic acid in most of tested berries with the exception of blackberry cultivars, where malic acid was dominant. The content of individual phenolic compounds varied among the wild species, as well as among the studied cultivars. Ellagic acid content was higher in F. vesca, R. idaeus and R. fruticosus (122.5 µg/g FW, 12.71 µg/g FW and 61.7 µg/g FW, respectively) than that obtained in analyzed cultivars. Overall, TPH expressed higher values in the wild strawberry and blackberry species in comparison to the studied cultivars, and consequently, the highest levels of TAC were recorded in F. vesca (5.78 mg asc/g FW), followed by R. fruticosus (4.95 mg asc/g FW).

PRACTICAL APPLICATIONS

In recent years, both wild and cultivated berries have become very attractive for consumers because of potentially beneficial phytochemicals contained in these fruits. Fruit nutritional quality can be described by standard quality parameters (sugars and organic acids), and the analysis of antioxidant capacity influenced by specific related compounds. The importance of flavonoids and other phenolics have been suggested to play a preventive role in the development of cancer and heart disease. A significant positive correlation observed in this study between total phenolics and total antioxidant capacity indicate the need for the use of wild species in the breeding programs of small fruits, especially strawberry and blackberry, in order to increase their nutritive value and the health benefits.     

新合纤及其制造加工技术

说明了日本新合纤(新聚酯)的发展阶段,介绍了国外(日本西欧和美国)新合纤的市场情况,指出了日本在新合纤领域目前处于世界最先进水平。概括了新合纤制造加工技术及1990～1992年间日本各合成纤维厂商推出的新合纤产品。最后指出了新合纤存在的某些缺点。     

BARLEY AND MALT TANNINOGENS AND BEER QUALITY

Anthocyanogen and catechin contents (tanninogen values) were determined for ten two-row and thirteen six-row barleys and for their corresponding malts. Four barley-malts were then selected for brewing, one with high, one with low, and two with intermediate tanninogen contents. The brews were made using bottom-fermenting (lager) as well as top-fermenting (ale) yeasts, both at 50–55° F. and at 68° F. The quality of the beers, as expressed by standard analyses and flavour evaluation, is discussed in the light of the tanninogen contents of the barleys and the different brewing parameters (yeast type and fermentation temperature).     

姜与人体营养健康

对姜的营养、保健功能及其在日常生活中的应用进行了介绍，更利于推动我国调味品业的进一步研究与开发。     

Tencel机织物的染整加工及所用染化料

Ｔｅｎｃｅｌ纤维易于原纤化和很高的横向膨润性对染整加工设备选型、工序安排、染化料选用提出了很高的要求，关键的助剂是润滑剂、纤维素酶、柔软剂、树脂整理剂、防原纤化助剂，于是详细讨论了Ｔｅｎｃｅｌ机织物的前处理、初级原纤化、酶处理、染色、二次原纤化和柔性、树脂整理及染化料的应用。     

INSTRUMENTAL AND SENSORY TEXTURE ASSESSMENT AND FRACTURE MECHANISMS OF CHEDDAR AND CHESHIRE CHEESES

Textural attributes of Cheddar and Cheshire cheeses, falling within narrow compositional ranges, were assessed by sensory panels, and from force-compression curves generated by compression between two plates, and, for Cheddar cheese only, by penetrometry. Individual sensory measurements did not relate well to any instrumental one, and were better at discriminating between cheeses. Samples of each cheese variety were fractured in different ways and the fracture surfaces were examined in a scanning electron microscope. Fracture surfaces were formed by cutting directly through the matrix, tearing of the matrix along planes high in fat or cracking at grain boundaries. It is suggested that consideration of fracture mechanism may aid the selection and development of useful instrumental methods for texture assessment of cheese.     

AREA- AND PERIMETER-DEPENDENT PROPERTIES AND FAILURE OF MATURE-GREEN AND RED-RIPE TOMATO PERICARP TISSUE

The influence of tomato fruit ripeness on area- and perimeter-dependent properties and dominant failure mechanisms of pericarp tissue were investigated. Tissue discs from mature-green and red-ripe fruit were punctured with a flat-ended cylindrical probe and compressed with a flat plate at a constant rate of deformation. Approximately linear force-deformation curves were obtained to tissue failure by both puncture and flat plate compression, interrupted by a region of pseudoplastic deformation at a relatively low initial bioyield force. Based on estimated area- and perimeter-dependent coefficients and firmness (force/deformation) values, initial bioyielding of tissue appeared to be associated with an abrupt increase in cell-to-cell compaction. Puncture of mature-green tissue led to premature failure induced by shearing or rupture of tissue at the probe perimeter. The contribution to puncture of perimeter-dependent or shear-associated forces and a putative "zone of influence" increased markedly with ripening, while the contribution of area-dependent or compression associated forces generally decreased. A concomitant decrease in failure force and firmness with ripening reflected a general loss of both tissue compression and shear strengths. These results suggested that the dominant mode of tissue failure changed with ripening, from cell relaxation and rupture to cell debonding. The data obtained in this study emphasize the need to exercise caution in the interpretation of force-deformation parameters derived from puncture tests alone.     

THIOLS AND DISULPHIDES IN QUIESCENT AND GERMINATING BARLEY GRAINS,BOTH DORMANT AND MATURE

Reduced and oxidised glutathione, cysteine, cystine and traces (too small to quantify) of γ-glutamyl-cysteine and cysteinylglycine were detected, in about the same amounts, in extracts of the embryos of dormant and mature barleys. During micromalting the levels of the thiols and disulphides altered in various ways, but altered in the same ways in dormant and mature samples of grain until germination began. An early decline in the glutathione content of embryos was mirrored by a rise in the amount in degermed grains. Histochemical tests and analyses of isolated tissues showed that in the quiescent grains thiols were concentrated in the embryo (particularly the scutellum) and in the aleurone layer and isolated embryos released thiols into an incubation medium. We conclude that the endogenous thiols and disulphides are not obviously involved in the regulation of dormancy.