CHARACTERISTICS OF FRANKFURTERS WITH DIFFERENT COOKING PARAMETERS

The purpose of this study was to evaluate the effects of different reheating methods (steeping, broiling, or microwaving) and end-point reheating temperatures (66C, 77C, or 88C) on the physical and sensory characteristics of frankfurters. Instron hardness, shear force, sensory hardness, and saltiness scores increased and juiciness scores decreased with additional reheating temperature when frankfurters were microwaved or broiled. Frankfurter density decreased with higher ultimate temperature which was attributed to additional gas volume. Expressible moisture increased with a higher ultimate temperature when frankfurters were steeped. Free water was the highest at 77C. Neither cooking procedure nor ultimate temperature influenced protein denaturation as determined by gel electrophoresis and enzymatic digestion.     

不同生姜提取物的急性毒性研究

观察不同生姜提取物的急性毒性并对其进行评价.依据GB15193-2003(食品安全性毒理学评价程序和方法>进行急性毒性试验,研究生姜食品的急性毒性.生姜水提物和生姜醇提物对两种性别的小鼠经口毒性灌胃达66.67g/kg两周内动物未见明显中毒症状,无动物死亡.取灌胃1 d后与灌胃前的体重差值及灌胃一周后及灌胃前的体重差值做为小鼠长势的数据描述进行分析.经口急性毒性作用试验表明生姜无毒级物质.结论:生姜具有较好的食用安全性.     

PHYSICAL CHARACTERISTICS OF BEEF ROASTS PREPARED WITH DIFFERENT FOODSERVICE COOKING METHODS

Effects of cooking rate, fat trim level, aging period, endpoint temperature and oven type (conventional, forced air convection and forced air/steam combination) on yield, composition and cooking parameters for eight types of beef roasts were investigated. Generally, fast cooking, higher endpoint temperatures, complete removal of external fat and the use of forced air/steam combination ovens increased cooking losses. Fast cooking rates and forced air/steam combination ovens increased moisture loss in some roasts. Reduced levels of external fat did not dramatically affect yields or relative changes in composition due to cooking, but did increase cooking time per unit weight. Forced air/steam combination ovens may reduce the required length of preparation per unit raw weight while conventional ovens may increase cooking time. Rapid cooking of larger roasts with moist heat increased postcooking temperature rise. These results should aid in the revision of foodservice beef cookery guidelines.     

CHANGES IN COOKING AND TEXTURAL PROPERTIES OF SPAGHETTI COOKED WITH DIFFERENT LEVELS OF SALT IN THE COOKING WATER

The effect of cooking water on textural and cooking properties of spaghetti was examined using four different salt concentrations 0, 1, 2, 3 and 4% in the cooking water and two types of spaghetti. Brand A was normal durum wheat spaghetti and brand B was spaghetti enriched with bran. Regardless of the cooking water used, brand B was harder, less sticky than brand A and it absorbed less water. Brand A required less cooking time. As salt concentration increased cooking time and hardness scores increased. Adhesiveness values were highest at the early stages of cooking and declined as cooking time increased.     

GINGER RHIZOME: A NEW SOURCE OF PROTEOLYTIC ENZYME

The proteolytic activity of ginger rhizome was studied with bovine serum albumin (BSA), collagen and actomyosin as substrates. A semipurified, powdered enzyme preparation was prepared by buffer extraction of an acetone powder of ginger rhizome and subsequent acetone precipitation of the proteolytic principle from the buffer extract. With 3% BSA as substrate, a relatively high proteolytic activity occurred over a pH range of 4.5–6.0, with an optimum pH of 5.0. The optimum temperature for proteolysis of BSA was 60°C during a 10 min reaction time, with rapid denaturation of the enzyme occurring at 70° C. NaCl in cone up to 10% produced about a 20 and 50% reduction in proteolysis of collagen and BSA, respectively. The ginger protease was protected by dithiothreitol during extraction and reaction, indicating the involvement of −SH groups at the active site. The analyses of soluble peptide amino acids or terminal amino acids suggest that the proteolysis of collagen is many fold greater than that of actomyosin. The combined proteolysis of these two muscle protein fractions by the ginger protease resulted in significantly more tender meat. According to conventional nomenclature, "Zingibain" is the proper name for this proteolytically active principle in Zingiber officinale roscoe or ginger rhizome which is commonly referred to as gingerroot. For meat applications, a possible advantage of zingibain over papain and ficin is the greater proteolysis of collagen in comparison to actomyosin. When compared to reported values for bromelain, zingibain has a higher optimum activity temperature, which is desirable in some applications     

PALATABILITY OF BEEF ROASTS PREPARED WITH DIFFERENT FOODSERVICE COOKING METHODS

Effects of cooking rate, fat trim, aging, endpoint temperature and oven type (conventional, forced air convection and forced air/steam combination) on the palatability of beef foodservice roasts were investigated. Clods, chuck rolls, ribeyes, tenderloins, knuckles, inside rounds, gooseneck rounds and steamship rounds were included in the study. Differences in palatability, due to the cooking methods evaluated, were not consistent across all roast types, but the cooking method affected (P < 0.05) palatability traits in all roasts. Inconsistency was most likely due to varying size, composition and shape. Longer aging periods increased tenderness in ribeyes and gooseneck rounds. Palatability was only affected by oven type in round subprimals. First principal component scores (PRINI) were related to palatability and were used to rank treatment levels within main effects when substantially different from zero. Palatability was maximized within main effects inconsistently across different roast types when sorted by PRINI.     

THE ANTIOXIDATIVE POTENTIAL OF LYOPHILIZED CITRUS PEEL EXTRACT IN DIFFERENT MEAT MODEL SYSTEMS DURING STORAGE AT 20C

Antioxidative potential of lyophilized citrus (Citrus unshiu) peel extract in raw and cooked meat systems was investigated. Beef pork, chicken, and salmon patties were prepared without (control), with lyophilized citrus peel extract (0.1%, NICP), and with 20 kGy-irradiated, lyophilized citrus peel extract (0.1%, ICP). TBARS value showed that the addition of lyophilized citrus peel (NICP or ICP) inhibited the development of lipid oxidation of raw and cooked meat patties during storage for 8 days at 20C (P<0.05) except for raw chicken patty. Hunter color a*-values of the cooked meat patties treated with NICP or ICP were higher than those of the control (P<0.05). Irradiation of citrus peel extract did not show any notable changes in its antioxidant effect in the meat systems. Thus, the lyophilized citrus extract could be used as one of the natural antioxidants with the potential of cost-effectiveness and is environmentally friendly.     

不同储期酸奶对小鼠免疫功能和游泳耐力的影响

探讨不同储期酸奶对小鼠免疫功能和游泳耐力的影响.以原味酸牛奶为受试物,试验分5组,每组20只,各组分别灌喂0.9%的生理盐水和储存0、3、6、9d的酸奶,1 mL/只·d,连续灌喂28d;对小鼠进行游泳耐力、腹腔巨噬细胞吞噬鸡红细胞、免疫器官指数、血清溶血素含量、血细胞计数的测定.酸奶可明显提高小鼠游泳耐力、巨噬细胞的吞噬率、脏器指数、血清溶血素的含量,增加血液中的白细胞、红细胞和血红蛋白的量;其中储存3 d的效果最好,其次是0d,6d和9d次之.酸奶可以提高机体的免疫功能,尤其是储存了3d的酸奶.     

CHANGES IN THE CHARACTERISTICS OF ROHU FISH (LABEO ROHITA) SAUSAGE DURING STORAGE AT DIFFERENT TEMPERATURES

Sausage is a commonly used food and it is gaining wide popularity in the recent years. In this work, sausage was prepared from minced Rohu ( Labeo rohita ) fillets using a standard recipe with and without addition of the preservative, potassium sorbate, in permitted levels and packed in natural casings. The prepared sausages showed appealing appearance with characteristic resilient properties. The evaluation of their physical, chemical, organoleptic and microbiological characteristics during storage at 5 and 25C was carried out. After 2 days of storage at ambient temperature, the control samples (without potassium sorbate) lost their cohesive nature and appeared pasty and sticky, accompanied by water oozing out and detachment from the casing due to fermentation and subsequent gas formation, as evidenced by fermented odor, decreased pH and increased total bacterial count. In the case of samples with potassium sorbate (treated), these symptoms of spoilage were observed after 4 days of storage. Similarly, the control samples at refrigerated temperature (5C) were found spoiled after 13 days of storage and those with the preservative were spoiled after 16 days.

PRACTICAL APPLICATIONS

Acceptability of freshwater fish to the market can be increased by value addition. Sausage is already a well-accepted product in the commercial market. Freshwater fish has a muddy flavor, which is an unpalatability for consumption. Therefore, we introduced the addition of mint to avoid the muddy flavor. We tried different storage conditions for the sausage and tried the effect of potassium sorbate for increasing shelf life. Spices such as cloves, cinnamon, ginger, etc., were added to the sausage, which were also found to increase the shelf life. From the study, we have optimized the suitable temperature and storage days for obtaining the acceptable product.     

FORMATIONS OF BIOGENIC AMINES IN TURKISH STYLE SAUSAGE DURING RIPENING AND STORAGE PERIODS

Changes of biogenic amine (histamine, β‐phenylethylamine, serotonin, spermine, spermidine, cadaverine, putresine, 1,7‐diamino heptane, tryptamine and tyramine) concentrations and pH values of Turkish style sausages were investigated during ripening and storage. Cadaverine and β‐phenylethylamine were not detected during the ripening and storage periods for all sausage types. Storage time had a significant (P<0.05) effect on the formation of all biogenic amines. Starter culture usage decreased (P<0.05) biogenic amine formation. Histamine levels were higher in sausages prepared without additives and lower in the sausages made with starter culture than the sausages made without starter culture. There was no effect of starter culture and additives on formation of tryptamine, 1,7‐diamino heptane, serotonin or spermidine. Starter culture and additives affected (P<0.05) the formation histamine, putrescine and spermine. pH values of sausages sharply decreased (P< 0.05) from 5.98 to about 4.53 during 3 days of ripening. After that, pH values increased slowly and were nearly constant during the storage period.     

超临界CO2萃取姜挥发油及GC-MS分析

正交试验法时超临界CO2提取生姜挥发油的提取条件进行研究.结果表明,最佳提取条件为:原料粒径为03mm,萃取压力25 MPa,温度40℃,CO2流量30 kg/h,萃取时间100min,所得姜精油呈浅黄色,得率由传统水蒸气蒸馏法的1%左右提高到4.38%.采用气相色谱-质谱联用技术测定最佳提取条件下所得生姜挥发油的化学成分及其相对质量分数,共分离出58种成分并鉴定出其中38种,主体呈香成分为柠檬烯、α-蒎烯、莰烯、金合欢烯、β-水芹烯、β-倍半水芹烯、姜烯等烯类.主体辣味成分为6-姜醇.     

RETENTION OF VITAMINS IN FRESH AND FROZEN BROCCOLI PREPARED BY DIFFERENT COOKING METHODS

Fresh and frozen broccoli were analyzed for retention of ascorbic acid, riboflavin and thiamine by semi-automated fluorometry before and after steaming, boiling or microwave cooking for 5 min. Retention of vitamins in general was higher for fresh than for frozen broccoli. Steamed fresh broccoli retained most ascorbic acid, riboflavin, and thiamine. Boiled fresh samples retained least riboflavin and ascorbic acid and microwaved samples, the least thiamine. In frozen broccoli, microwaved samples retained most ascorbic acid and riboflavin, and steamed samples retained most thiamine.