Supplementation of Protein Hydrolysates to a Low‐fishmeal Diet Improves Growth and Health Status of Juvenile Olive Flounder,Paralichthys olivaceus

An 11‐wk feeding trial was conducted to evaluate three different protein hydrolysates as feed ingredients in high‐plant‐protein diets for juvenile olive flounder. Five experimental diets were fed to juvenile olive flounder to examine the effect of three different protein hydrolysates on growth performance, innate immunity, and disease resistance against bacterial infection. A basal fishmeal (FM)‐based diet was regarded as a high‐FM diet (HFM) and a diet containing soy protein concentrate (SPC) as a substitute for 50% FM protein was considered as a low‐FM diet (LFM). Three other diets contained three different sources of protein hydrolysates, including shrimp, tilapia, and krill hydrolysates (designated as SH, TH, and KH), replacing 12% of FM protein. All diets were formulated to be isonitrogenous and isocaloric. Triplicate groups of fish (15.1 ± 0.1 g) were handfed one of the diets to apparent satiation twice daily for 11 wk and subsequently challenged against Edwardsiella tarda. Growth performance and feed utilization of fish fed hydrolysate‐supplemented diets were significantly improved compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates significantly enhanced apparent digestibility of dry matter and protein of the diets. In the proximal intestine, histological alterations were observed in the fish fed the LFM diet. The fish fed the hydrolysate diets showed significantly longer mucosal fold and enterocytes and greater number of goblet cells compared to fish fed the LFM diet. Respiratory burst activity was significantly higher in fish fed the TH and KH diets than fish fed the LFM diet. Significantly higher immunoglobulin levels were found in fish fed SH and KH diets compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates in SPC‐based diets exhibited the highest lysozyme activity. Significantly higher superoxide activity was observed in groups of fish fed the KH diet. Fish offered the protein hydrolysates were more resistant to bacterial infection caused by E. tarda. The results of this study suggest that the tested protein hydrolysates can be used as potential dietary supplements to improve growth performance and health status of juvenile olive flounder when they were fed a LFM diet.     

改性脲醛树脂粘合基质块性能及其对黄瓜幼苗生长的影响

针对机械化移栽过程中,基质容易散落,造成根系损伤的问题,该研究采用了既具有粘合性又具有养分释放功能的生物降解胶黏剂粘合基质成块。测定了水解蛋白改性脲醛树脂的基本性能,基质块的孔隙度、EC值、pH值和抗压强度的变化规律,以及基质块对黄瓜幼苗生长的影响。试验结果表明,该改性脲醛树脂的氮素释放速率前期缓慢,后期较快,在第7周时养分释放率可达48%。添加50%改性脲醛树脂后,基质块的总孔隙度下降约8.4%,但还是能够满足黄瓜生长需要。然而添加改性脲醛树脂后基质块的EC由2.51 mS/cm下降到1 mS/cm左右,pH值基本保持不变。改性脲醛树脂在添加量50%时,抗压强度为0.14 MPa以上,能够满足机械手抓取的要求,也能够满足幼苗根系生长的要求。同时,叶面积、鲜质量、干质量比普通基质提高了89.86%、57.00%、79.2%。III-UF改性脲醛树脂的养分释放速率与黄瓜幼苗生长养分需求速率是一致的,该配方最有利于黄瓜幼苗的生长。添加胶黏剂后,每个颗苗只需增加0.0125元,从成本上看价格便宜,有利于推广应用。     

Comparative studies on dietary protein requirements of juvenile and on‐growing gibel carp (Carassius auratus gibelio) based on fishmeal‐free diets

Two trials were conducted to investigate protein requirements of juvenile (3.18 g in Trial 1) and on‐growing (87.1 g in Trial 2) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets containing 250–500 g kg^?1 dietary protein were formulated using soy protein concentrate (SPC) and casein as protein sources. The results showed that weight gain (WG) increased when dietary protein increased from 250 to 400 g kg^?1 and decreased at 400 to 500 g kg^?1 CP in Trial 1, while WG increased when dietary protein increased from 250 to 350 g kg^?1 and kept constant at 350 to 500 g kg^?1 CP in Trial 2. With increasing dietary protein, feed conversion ratio (FCR) decreased, while protein retention efficiency (PRE) decreased in Trial 1 and was not affected in Trial 2. Apparent digestibility coefficient of protein (ADC_p) increased with increasing dietary protein in two trails. Trypsin activity increased with dietary protein in the juveniles and was not affected in on‐growing fish. Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities increased with dietary protein. Broken‐line and quadratic regression of WG estimated that dietary protein requirements for maximum growth were about 402–427 g kg^?1 for the juvenile and 337–418 g kg^?1 for on‐growing gibel carp.     

毛豆氮磷钾肥效应及推荐施肥量的研究

通过田间试验研究毛豆施用氮磷钾肥料的效应,结果表明:N2P2K2处理毛豆的平均产量比不施肥处理增产17.9%,说明施肥对毛豆具有显著的增产作用。毛豆施用氮磷钾肥料平均分别增产16.0%、6.8%和6.1%,增产效果为N>P>K。氮磷钾肥的平均产投比分别为4.5、3.2和2.4;氮磷肥在中高肥力土壤的产投比较高,钾肥则在中低肥力土壤的产投比较高。平均推荐施用量为纯N 202 kg/hm2、P2O5 81 kg/hm2和K2O 100 kg/hm2,其预测产量为20 719 kg/hm2,三要素最佳比例为1∶0.40∶0.50。     

不同工艺生产大豆分离蛋白的成膜性能

为了制作出具有良好机械性和阻隔性的大豆分离蛋白可食性膜,优选出成膜性能优良的大豆分离蛋白,该文研究了7种不同生产工艺下的大豆分离蛋白,分别以7种蛋白为材料制膜,测定其机械性能、水溶性、水蒸气透过性、O2透过性、脂质渗透性等性能,进行模糊综合评价,并用扫描电镜观察膜的表面结构。结果表明:GS5000型普通型未经造粒的大豆分离蛋白综合评价分数最高,表明其成膜性能优于其他6种大豆分离蛋白,并且电镜扫描照片也显示用其制出的膜结构更加致密,因此,GS5000型大豆分离蛋白比较适合制作可食性膜。该研究为进一步开发优质大豆分离蛋白膜进行了初步的探索。     

扬州豆腐干风味制品核辐照综合保质技术研究

豆腐干是扬州名菜大煮干丝的原料,过去由于沿用传统工艺制作,保质期短,外地淮扬菜馆难以经营,本研究通过改进生产工艺,对产品实施真空包装和8kGy的辐照处理,可实现4℃保藏3个月的目标。将此技术应用于茶香干、酱干相关制品,结果表明,处理后的产品25℃可保藏3个月,4℃可保藏4个月,应用于大煮干丝可在4℃下保藏2个月。     

大豆蛋白-三聚氰胺-尿素-甲醛树脂胶黏剂固化剂的研究

以大豆蛋白降解液、三聚氰胺、尿素和高浓度甲醛为原料,合成了一种低摩尔比的大豆蛋白-三聚氰胺-尿素-甲醛共缩聚树脂胶黏剂(SMUF)。选用(NH4)2SO4、(NH4)2S2O8、(NH4)2HPO4和H3PO4作为SMUF树脂的固化剂,研究了固化剂对SMUF树脂基本理化性能的影响。结果表明:1)传统固化剂(NH4)2SO4不能使SMUF树脂充分固化,最终树脂胶合强度低、耐水性差,固化后的胶层断面疏松、多孔;2)H3PO4和(NH4)2S2O8属于中强酸体系,两者均能一定程度加速SMUF树脂的固化,树脂胶合强度和耐水性均得到改善,固化温度显著降低,固化放热量有所提高;3)(NH4)2HPO4是一种缓冲型酸,其催化SMUF树脂的固化速度较为均匀,树脂综合性能较优,树脂的胶合强度和耐水性较好,固化温度也有所降低,树脂交联程度高,树脂固化层断面相对较为均匀。     

玉米蛋白粉在制酱中的应用

用玉米淀粉副产物－米蛋白粉代替部分大豆做为原酱的蛋白质原料,采用固态低盐法进行发酵,其产品的感官指标和理化指标优于或接近传统酱。     

不同热处理温度下转谷氨酰胺酶对混合蛋白凝胶性的影响

通过十二烷基磺酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)研究不同热处理温度条件下转谷氨酰胺酶(TG)催化大豆分离蛋白(SPI)和肌原纤维蛋白(MPI)的凝胶特性。在超纯水环境中用TG处理SPI,在大于50℃的加热条件下所有SPI组分(除了球蛋白B亚基)都共价结合成大的杂聚物而无法进入分离胶。TG处理MPI后,所有MPI成分[除肌动蛋白(Actin)外],在60~90℃均能交联,并形成有序的高弹性凝胶结构。经TG处理的MPI/SPI混合蛋白,大量SPI使肌球蛋白重链和肌动蛋白变为低分子多肽,同时,TG催化MPI与SPI交联在进样端产生1条深色电泳条带(大豆蛋白中除基本亚基外的7S和11S两个亚基)。     

Protein and starch digestibilities and mineral availability of products developed from potato,soy and corn flour

A technique for development of potato flour was standardized. Five products viz. cake, biscuit, weaning food, panjiri and ladoo were prepared incorporating potato flour, defatted soy flour and corn flour. Baking and roasting were the major processing techniques employed for the development of these products. Protein, ash and fat contents of potato flour were almost similar to those of raw potatoes. Significant differences in protein, ash and fat contents of all the products were observed. Protein and starch digestibility of potato flour was significantly higher than that of raw potatoes. Protein digestibility increased by 12 to 17 percent on baking or roasting of products. Processed products had significantly higher starch digestibility and mineral availability compared to raw products. Thus, it can be concluded that roasting and baking are effective means of improving starch and protein digestibility and mineral availability of products.