ENZYMATIC MODIFICATION OF BORAGE OIL: INCORPORATION OF EICOSAPENTAENOIC ACID

Borage oil ( Borago officinalis L.) fatty acid composition was modified to incorporate eicosapentaenoic acid (EPA), with an immobilized nonspecific SP435 lipase from Candida antarctica as biocatalyst. Transesterification, between borage oil and EPA ethyl ester (EEPA) was carried out in hexane. Incorporation increased with increasing concentration of EEPA. An enzyme concentration of 20% gave 31% EPA incorporation into borage oil. As the incubation time increased, EPA incorporation was also increased up to 36 h.     

酶法水解的亚铁肽微胶囊化的工艺研究

以麦芽糊精和β-环糊精为壁材，采用超声波法包埋亚铁肽形成微胶囊，通过正交试验研究了微胶囊化过程中的最佳工艺条件。结果表明：用超声波法制备亚铁肽的最佳工艺条件是：芯壁比为1：6，麦芽糊精：β-环糊精为70％：30％，包埋时间为20min，糊精浓度为33％，亚铁肽的包埋率可达80％以上。     

INCORPORATION of MILK PROTEINS HARVESTED BY DIRECT ACIDIFICATION INTO PROCESS CHEESE PRODUCTS

Casein curd, a 5:1 combination of casein curd and lactalbumin, traditional coprecipitate curd, and Hiddink's coprecipitate curd were each used to replace varying amounts of natural cheese protein in a process cheese product. Traditional coprecipitate was used successfully to replace up to 40%, and Hiddink's coprecipitate up to 50%, of natural cheese protein in an experimental product. At higher levels of replacement, the product mixtures would not become homogeneous. Casein, and the combination of casein and lactalbumin, were used to replace up to 80% of natural cheese protein in an experimental product. Experimental products were compared rheologically to a group of similar use commercial products. Stress-strain, stress relaxation, and creep behavior indicated that the experimental products were generally more rigid than the commercial products. the meltability of all the experimental products was similar to that of the commercial products.     

大豆水化油脚酶法改性研究

用磷脂酶A1水解大豆油脚中磷脂制备溶血磷脂产品。通过正交试验得到磷脂酶A1水解的最佳反应条件：反应温度60℃、加酶量4U／g、反应时间5h，在该条件下水解产品的酸值为60．65mgKOH／g。用高效液相色谱（HPLC）对水解前后原料和产品进行了分析，知最佳条件下磷脂酶A1水解水化油脚的水解率为90．2％。     

REDUCTION OF ALLERGENICITY AND INCREASING THE BIOLOGICAL VALUE OF BUFFALO'S MILK PROTEINS BY ENZYMATIC MODIFICATION

Buffalo milk proteins were covalently enriched with methionine (Met) during the enzymatic peptide modification (EPM) process. The maximal Met-enrichment occurred when the α-chymotryptic hydrolysate of buffalo's milk proteins was treated with methionine ethyl ester in the presence of α-chymotrypsin during the EPM. Methionine content of this product was more than three times (5.4%) higher than that of the original buffalo milk protein (1.5%). The electrophoretic patterns of the modified proteins showed that the enzymatic reaction was mainly characterized by transpeptidation. Molecular masses of the modified protein fractions were influenced by the concentration of L-methionine ethyl esters in the reaction mixture during the EPM. EPM products from the buffalo milk protein hydrolysates with α-chymotrypsin and trypsin or with pepsin and trypsin showed low allergenic activities compared with those when buffalo milk proteins were hydrolyzed with α-chymotrypsin or with pepsin alone.     

METHIONINE LIBERATION BY PEPSIN-PANCREATIN HYDROLYSIS OF BEAN PROTEIN FRACTIONS: ESTIMATION OF METHIONINE BIOAVAILABILITY

Albumin (ALB), globulin (GLO), globulin G1 (G1), glutelin (GLU), and a protease inhibitor-lectin rich fraction (PIL) were extracted from IAC-Carioca 80 SH (Phaseolus vulgaris) based on differential solubility. The purpose of the study was to search for different susceptibilities to proteolysis and methionine liberation among protein fractions. The fractions were submitted to pepsin digestion for 3 h, then to pancreatin digestion for another 3 h, under optimum pH and 37C. Degree of hydrolysis (DH) was followed by the TNBS reaction and methionine liberation (Met%) by the chloramine-T method. DH for undenatured proteins was higher for GLO, Gl and GLU (62–71%) and lower for ALB and PIL (51–53%). After denaturation, DH was higher for Gl, GLU and GLO (81–86%) and lower for PIL and ALB (66–78%). For undenatured proteins Met% was higher for GLO, Gl and GLU (42–48%), and lower for ALB and PIL (22–29%). For denatured proteins Met% was higher for Gl, ALB and GLO (66–73%) and lower for PIL and GLU (50–53%). Overall, hydrolysis and methionine liberation followed the same general pattern for both pepsin and pancreatin digestion, individually.     

INCORPORATION OF MINCED TROUT (ONCORHYNCHUS MYKISS) INTO EGG-BASED NOODLES

Recovering minced fish from fish frames following filleting operations is a common way to increase fish muscle yield as well as fully utilize aquatic food resources. Therefore, it is important to develop new and feasible applications for minced fish that will add value to fishery products. In this study, washed minced trout (Oncorhynchus mykiss) was incorporated at 10 and 20% flour replacement level into a conventional egg noodle formulation. Textural attributes (by TPA) of cooked noodles were evaluated. In addition, textural, functional and sensory attributes of fried noodles, a snack food item, were also evaluated. Visual color (CIE )‐Lab of fresh noodles containing minced trout was less red and yellow than the control and the overall difference in color (ΔE) increased as the level of minced trout increased. Noodles incorporating 10% minced trout had cooked texture profiles similar to the control; however, there were significant decreases in hardness, gumminess and chewiness in the cooked noodles containing 20% minced trout. For the fried noodles, adding fish tended to reduce the yellow color and yielded a product with texture profiles similar to the control at a 10% substitution level. The experimental and control products were acceptable. Product preference was evenly divided between the control fried noodle and the noodle containing 10% minced trout.     

PHOSPHATE AND NON-MEAT PROTEIN INCORPORATION INTO SMOKED SAUSAGE PRODUCED FROM MECHANICALLY DEBONED POULTRY MEAT

The effects of sodium tripolyphosphate and type of non-meat protein binders on the quality of smoked sausage produced from mechanically deboned poultry meat (MDPM) without skin were studied. Higher cook yields were observed in sausages containing soy protein isolate, soy protein concentrate and sodium caseinate (P < 0.05). Addition of sodium tripolyphosphate, with or without non-meat protein binder, also increased cook yields (P < 0.05). Objective and sensory textural attributes of firmness, chewiness and springiness were not affected by type of binder, but incorporation of phosphate increased sausage firmness. All chicken sausage treatments were considered acceptable by the sensory panel.     

CAROTENOPROTEIN FROM TROPICAL BROWN SHRIMP SHELL WASTE BY ENZYMATIC PROCESS

While extraction of carotenoprotein from brown shrimp (Metapenaeus monoceros) shell waste, trypsin showed maximum recovery (55%) of carotenoid pigment in 4 hours at (28±2°C); but pepsin and papain showed about 50% recovery during the same period. The yield of protein paste by trypsin was maximum. The average protein content in the protein paste was about 450 g kg^-1. The percent of recovery of protein by papain and pepsin was close to that of trypsin. During storage at ambient temperature (28±5°C) loss of carotenoids from cake prepared by trypsin was minimum. The cost of trypsin is twenty times that of papain. Thus papain, easily available and the cheapest enzyme, can be used suitably for moderate recovery of carotenoids and good recovery of protein from shrimp shell waste at tropical ambient temperature. The dried colorless solid residue after extraction of carotenoprotein and protein, can be used as raw materials for chitin/chitosan.     

酶法提取麦冬多糖的工艺条件研究

采用单因素试验和正交试验,对酶法提取麦冬多糖的工艺进行研究,得到最佳工艺条件:料液比1:35、溶剂pH值5.0、酶用量0.5%、酶解温度45℃、酶解反应时间120min.采用酶水解后,麦冬多糖的提取率显著提高.     

淡水鱼鳞水解胶原蛋白的酶法制备

对几种常见淡水鱼鳞的基本成分和氨基酸组成进行测定,研究酶解鱼鳞制备水解胶原蛋白的工艺,并采取正交试验时水解条件进行优化.结果表明:淡水鱼鳞主要由蛋白质和灰分组成,粗蛋白含量高达55%以上;氨基酸组成显示淡水鱼鳞羟脯氨酸含量丰富,是制备水解胶原蛋白的良好原料.正交实验结果表明:55℃、E/S为3%、酶解2 h、底物浓度100 g/L时水解效果最好,此时,水解产物分子量较小,且分布集中.     

酶法提高青椒出汁率的研究

主要研究果胶酶、纤维素酶、半纤维素酶在提高青椒出汁率中的应用。结果表明，在单一酶试验中，果胶酶提高青椒出汁率效果最好，明显优于纤维素酶和半纤维素酶，纤维素酶次之，半纤维素酶相对较差。在复合酶试验中，果胶酶与纤维素酶按6：1复配，提高青椒出汁率效果最好。其在较佳酶解工艺条件：总酶用量0．0075％、加水量40％、酶解温度55℃、时间50min、pH3．0下，青椒出汁率可达74．4％，比单一果胶酶处理高出13．8％，比未经酶处理（23．4％）高出51％。