Protein quality measures determined in two allegedly poor quality fish meals and in two commercial capelin meals

Protein quality indices (PER, nitrogen balance, digestibilities of protein, methionine and lysine) were obtained for two allegedly poor quality fish meals of unknown origin and for two Norwegian capelin meals. The former two contained 40 and 50%, the latter two, 6 and 12% of their methionine in the form of methionine sulphoxide. A high sulphoxide content was associated with poor protein quality. Thus, autoxidation during production or storage may affect fish meal protein differently from oxidation with hydrogen peroxide in the laboratory. Methionine supplementation did not improve the PER-values of any of the meals. This indicates that methionine was probably not the first limiting amino acid for protein utilisation in these meals for the young rat.     

Effect of Partial Methionine Oxidation on the Nutritional Quality of Soy Isolate and Casein

The bioavallabllity of methionine sulfoxide residues in two food proteins, casein and soy isolate, was determined in weanling (21- day-old) and mature rats (101-day-old). Methionine sulfoxide residues within these two proteins had no significant effect on protein digestibility in either group of rats or on the growth of mature rats, but slowed the growth of weanling rats. The impact of methionine sulfone on the protein efficiency ratio (PER) bioassay for protein nutritional quality, which uses weanling rats, was also measured. Results from this study indicated that for each 10% of the methionine residues which are present as partially oxidized methionlne sulfone, the PER of the protein is lowered by 0.085 units.     

不同烹饪方式处理的鲟鱼肉营养成分和风味比较

为了探究烹饪方式对鲟鱼肉的蛋白质营养价值和风味物质含量的影响,该研究以人工养殖的鲟鱼肉为原料,比较了清蒸和煎炸烹饪方式,对鲟鱼肉的基本营养物质、氨基酸、蛋白质、风味化合物含量,以及氨基酸指数(AAS、EAAI)、蛋白质效价的影响,结果表明,以生鱼肉为对照,清蒸和煎炸使鲟鱼肉的水分含量分别降低了56.41％和43.73％...     

Nutritive value of meat meals. I. Possible growth depressant factors

When fed as supplements in a well-balanced diet for the rat, a commercial meat-meal sample and various heat-damaged laboratory preparations including pure tendon stimulated growth, thus providing contradictory evidence to previous reports of possible toxicity in such materials. An increase in dietary ash level, similar to that brought about by addition of meat meal, caused no growth depression in rats given, as their sole source of protein, gut preparations low in ash. Freeze-dried tendon had as low a value as oven-dried tendon in sole protein experiments in which rats lost weight and died. Meat meal itself supported slow growth and no further response was obtained with supplements of methionine, cystine, tryptophan and lysine.     

Hypoglycemic effect and protein nutritive quality of soy and methionine-supplemented whole durum pasta products

New low cost, high-protein and high-fiber pasta products processed from whole durum meal (WD) solely. WD supplemented with 7% or 12% defatted soy flour (SF). or 12% SF plus 0.3% methionine were evaluated in comparison with the regular pasta made of pure durum semolina (DS). Their protein nutritive quality was biologically evaluated by rat growth studies using diets containing 9% protein, through the parameters: food efficiency ratio (FER), protein efficiency ratio (PER), net protein utilization (NPU), digestibility coefficient (DC) and biological value (BV). The original products were administered to diabetic hypercholesterolemic albino rats. (injected with alloxane) to study their effects on the levels of blood glucose and plasma lipid fractions. The results indicate that diets based on pasta made of WD supplemented with SE or SF plus methionine had superior protein quality and succeeded in supporting normal growth of rats in contrast to the diets based on pasta made of unsupplemented WD or DS. These assays demonstrated that the values of FER, PER. NPU and BV of WD-pasta increased with increasing SF supplementation. However, high-fiber pasta made of unrefined WD solely or with SF had lower DC values compared to that of the regular DS-pasta. DC values decreased as the added SF increased. Adding methionine evidently affected FER. PER, BV and NPU values. Administration of high-protein and high-fiber pasta samples made of WD solely, supplemented with SF or SF plus methionine significantly reduced the elevated blood glucose as well as plasma cholesterol and plasma lipid fractions in hypercholesterolemic diabetic rats. Overall, considering nutritional evaluation, protein cost as well as hypoglycemic and hypocholesterolemic effects the pasta composed of 12% SF-WD and supplemented with 0.3% methionine represented the best high-fiber: high-protein and high-quality product.     

Nutritional evaluation of meat–soya bean protein product blends

The nutritive value of protein of blends consisting of meat and soya bean protein products, which replaced either 20 or 40 % of protein of meat, were determined in rat feeding experiments. Protein efficiency ratio (PER) and net protein utilisation (NPU) were significantly lower (P<0.05) in blends containing either 20% protein from soya isolate or 40% protein from soya concentrate or soya flakes than blends containing sirloin only. However, there were no significant differences in PER and NPU when model meat (consisting of 70 and 30% protein from sirloin and connective tissue, respectively) was replaced by up to 20% protein from soya isolate or up to 40% protein from soya concentrate.     

Physical and processing properties of milk,butter, and cheddar cheese from cows fed supplemental fish meal

Physical, chemical, sensory and processing properties of milk produced by feeding a rumen-undegradable fish meal protein supplement to Holstein cows were investigated. The supplement contained (as fed basis) 25% soft-white wheat, 60% herring meal, and 15% feather meal. The total fat level in the milk decreased to 2.43%. For both pasteurized and ultra-high temperature processed drinking milk, no difference was found between fish meal (FM) milk and control milk in terms of color, flavor and flavor stability; in particular, no oxidized flavor was observed. Cheddar cheese made from FM milk ripened faster after 3 mo of ripening and developed a more desirable texture and stronger Cheddar flavor. The yield efficiencies for FM and control cheese, 94.4 (+/- 2.44 SE) and 96.4 (+/- 2.26 SE), respectively, were not different. Relative to controls, average fat globule size was smaller in FM milk and churning time of FM cream was longer. FM butter had softer texture and better cold spreadability, and butter oils from FM enriched milk had lower dropping points compared to control butter oil (average 32.89 versus 34.06 degrees C). These differences in physical properties of butter fat were greater than expected considering that iodine values were not different. This study demonstrates the feasibility of producing high quality products from milk naturally supplemented with FM, but the results also show that dietary changes affect processing properties.     

Determination of the first-limiting amino acid for milk production in dairy cows consuming a diet of grass silage and a cereal-based supplement containing feather meal

Lactating dairy cows consuming a diet of grass silage and a cereal-based supplement containing feather meal were given intravenous infusions of amino acids to determine the first-limiting amino acid for milk production, methionine having been shown to be not-limiting in a previous experiment. The three infusion treatments were a mixture of methionine, lysine, histidine and tryptophan (4AA); the mixture without lysine (-Lys); and the mixture without histidine (-His). The 4AA treatment markedly increased the yield of milk protein by about 18% and this response was not diminished by omission of lysine. However, exclusion of histidine produced no response over basal, confirming histidine as the first-limiting amino acid. In a second experiment, lactating cows receiving a similar basal diet were used to examine the effects on milk production of progressively substituting avian blood meal (rich in histidine and poor in methionine) for part of the feather meal. Blood meal was substituted for 0, 0.10, 0.20 and 0.40 of the feather meal in the supplement. The yield of milk protein was increased by about 15% by the first level of inclusion of blood meal, but there was no further response beyond the first level of inclusion. The results of the feeding trial confirm that dietary addition of protein rich in histidine and of low ruminal degradability substantially increased milk production with this basal diet, although it should be noted that the calculated supply of all the essential amino acids were also increased, by varying degrees, by substitution of blood meal. The results of the two experiments are discussed in relation to the likely importance of histidine as a limiting amino acid in dairy cows consuming diets typical of those used in practice. © 1999 Society of Chemical Industry     

Nutritional Evaluation of Breadfruit-containing Composite Flour Products

Composite flours containing wheat, breadfruit flour and soy protein, whey or peanut meal were formulated and incorporated into western style bread and biscuits. Bread containing 10% breadfruit flour and 5% whey, and biscuits containing 10% breadfruit flour and 5% soy protein were judged most acceptable in flavor, color, and texture. Breadfruit flour contained 4.4% protein and was lower in sulfur containing amino acids and higher in lysine than wheat flour. Breadfruit containing bread and biscuits had low amino acid scores. The protein efficiency ratio (PER) of the biscuit product, however, was similar to that of the casein control while the PER of bread was significantly lower. Results suggest that acceptable products can be made with composite flours containing 10% breadfruit flour.     

Performance of dairy goats fed soybean meal or meat and bone meal with or without urea during early lactation

Use of meat and bone meal for early lactation rations was studied. In Experiment 1, 18 Alpine goats were used in a 15-wk lactation trial. Isonitrogenous and isoenergetic diets were fed (15% CP and 2.3 Mcal/kg metabolizable energy) containing soybean meal, meat and bone meal with urea, or meat and bone meal without urea. Dry matter intake was 2.21, 2.30, and 2.34 kg/d for does fed soybean meal, meat and bone meal with urea, and meat and bone meal without urea, respectively. Milk production was 2.50, 2.67, and 2.66 kg/d in the same sequence. Rumen ammonia N (mg/dl) and total VFA (mM) were 12.9 and 81.5, 21.4 and 76.3, and 12.2 and 81.6 for does fed soybean meal, meat and bone meal with urea, and meat and bone meal, respectively. Serum urea N was higher in does fed meat and bone meal with urea, and no differences were observed in serum total protein and plasma glucose concentrations. In Experiment 2, 4 mature, castrated male goats were used to estimate digestibilities and retention of nutrients in three diets. Digestibilities of NDF and P and retention of P were higher in goats fed the meat and bone meal diet. Allowance of absorbed protein for milk production was calculated to be 81 to 83 g/kg 4% FCM. Meat and bone meal may be utilized efficiently by lactating does as a protein less degradable in the rumen, Ca, and P source; and may be beneficial for higher milk production during early lactation.     

Pork quality from pigs fed on low glucosinate rapeseed meal: Influence of level in the diet,sex and ultimate pH

The appearance and eating quality of pork M. longissimus lumbrum from gilt and castrate pigs fed on diets containing a low glucosinate/low erucic acid rapeseed meal (cv. Tower) were assessed and compared with pork from pigs fed diets containing soya bean meal. At 90 kg liveweight, higher levels of either protein supplement, and therefore higher levels of dietary protein, gave slightly leaner meat. Meat from pigs fed rapeseed meal had more haem pigment and was slightly darker and redder than that from soya bean fed pigs. Differences in the quality of pork from the low glucosinate rapeseed meal and soya bean diets were small. Ratings for texture, juiciness and flavour of the lean varied little between the treatment groups. Suggestions that rapeseed meal as a protein supplement in diets might lead to inferior quality meat were not substantiated. The ultimate pH varied from 5.3 to 7.1 independently of the treatments and provided, for the first time, definitive relationships between pH and eating quality. Toughness and flavour were maximum and juiciness was a minimum after roasting meat of about pH 5.9. The ultimate pH had a larger effect on organoleptic quality than either sex or level of dietary inclusion of rapeseed or soya bean meals.     

Bound chlortetracycline residues in bones: release under acidic conditions

Tetracycline residues were frequently found in the bones of slaughtered animals. These bound residues will contaminate products for human consumption, such as mechanically deboned meat. The aim of this study was to examine the behaviour of bound residues of chlortetracycline during in vitro digestion. Dough batches containing poultry meat and 2.5% by weight of bone splinters and bone meal with chlortetracycline residues were incubated with hydrochloric acid and pepsin at 40°C. With the aid of HPLC and agar diffusion tests, evidence was obtained that these bound residues of chlortetracycline could be released during in vitro digestion and become antimicrobially active. Hens fed with chlortetracycline containing meat and bone meal were also able to release bound tetracycline residues.     

Nutritional evaluation of a cauliflower leaf protein concentrate by rat feeding

A leaf protein concentrate (LPC) prepared from cauliflower leaves was analysed for crude protein, calcium, phosphorus, iron, β-carotene and some of the amino acids. Lysine and tryptophan were present in nutritionally adequate amounts, but cystine and methionine were not: Cauliflower LPC was evaluated for its nutritional qualities in respect of growth rate, protein efficiency ratio (PER), liver nitrogen, and plasma protein content by feeding rats. The growth rate of rats and PER values of leaf protein supplemented diets were better than that of the wheat flour fed group. Hence, cauliflower LPC might be used for improving nutritionally poor diets.     

利用鸡骨酶解蛋白开发鸡肉香精产品的设计

肉类香精泛指具有肉类风味的一类食品添加剂,可广泛应用于肉类加工食品和方便食品,肉类香精通常被分为天然肉类香精与合成肉类香精两大类。以肉类蛋白酶解物、还原糖和半胱氨酸等物质为原料,辅以脂质等多种肉香风味的前体物质,通过热反应得到的合成肉味香精。本设计以鸡骨泥为原料,采用复合酶水解制备动物水解蛋白(HAP),再以HAP为基料,通过美拉德反应制备鸡肉香精,探究鸡肉香精的生产工艺。     

菠菜汁低温火腿肠加工工艺研究

以猪肉为主料，菠菜汁为配料，以玉米淀粉、大豆分离蛋白等为辅料，通过单因素试验和正交试验，针对菠菜汁低温火腿肠的配方进行了研究，结果表明：菠菜汁添加量为3％、肥瘦肉比例为7：3，淀粉添加量为10％、香辛料添加量1．5％，产品质量最好。     

胡萝卜鹅肉火腿肠配方的研究

以鹅瘦肉和胡萝卜为原料,以大豆分离蛋白和玉米淀粉为辅料,通过单因素试验,针对胡萝卜风味鹅肉火腿肠的配方进行了研究,结果表明:各种原辅料的最佳配比为,鹅瘦肉100kg,食盐2.8kg,玉米淀粉10kg,大豆蛋白2kg,水33kg,胡萝卜12kg,复合型香精0.4kg.     

Nutritive value of meat meals. II. Influence of raw materials and processing on protein quality

Commercial meat meals have shown low net protein utilisation values with rats of about 32, which is only 40% of the corresponding value for freeze-dried meat or gut. Biological assays for methionine and tryptophan, based on the weight gains of chicks, have shown a similar inferiority of meat meals despite 81–87% digestibility of their N. It is concluded that the lysine, methionine and tryptophan of the meat meals are approximately 80% available and that dilution of muscle protein with tendon and ossein in the raw material is at least as important as processing damage in reducing the quality of the products. It is argued that previous estimates of only 30% availability of methionine in meat meals are erroneous. Further problems in the use of values for fluorodinitrobenzene-available lysine and Streptococcus zymogenes-ayailable trytophan are discussed.     

Nutritional effects of including different levels and sources of protein in milk replacers for calves

Two digestibility and nitrogen balance experiments were carried out with groups of young calves given high-fat milk replacers reconstituted with water and fed in liquid form. In the first experiment six different milk replacers with crude protein contents ranging from 12.7 up to 27.6% in the dry matter were compared, the differences in protein content being brought about by adjustments to the level of separated milk protein used in the replacers. The apparent digestibility of organic matter was very high on all the treatments and unaffected by level of protein. Although the crude protein fraction showed an increase in apparent digestibility with increase in level of protein, its true digestibility was estimated to be virtually 100% on all the treatments. Retention of nitrogen expressed as a percentage of total intake remained fairly constant for diets containing from 18.8 to 27.6% of crude protein and the weight of nitrogen retained increased with each successive increase in level of dietary protein. In the second experiment the effects of replacing half of the milk protein in a control milk replacer by different forms of animal protein were studied. The true digestibilities of the total dietary protein on the treatment containing only separated milk protein and on the other treatments containing partial substitution by dried delactosed whey, dried blood, white fish meal and meat meal were found to be 94.1, 90.9, 85.4, 91.1 and 86.6%, respectively. Their biological values were 74.7, 70.3, 69.1, 66.0 and 65.5%, respectively. A sixth treatment in which the meat meal was provided with an enzyme supplement did not effect any significant change in either digestibility or biological value. Retentions of nitrogen expressed as percentages of intake were significantly lower on all the treatments containing partial replacement of separated milk protein by the other sources of protein than on the control treatment.     

THE POTENTIAL OF TERMINALIA CATAPPA (TROPICAL ALMOND) SEED AS A SOURCE OF DIETARY PROTEIN

The nutritional value of Terminalia catappa seed as a source of dietary protein was investigated. The crude protein content of the seed was high (25.81%). The amino acid analysis showed a good pattern of the essential amino acids (EAA) (in g/16 g N) - leucine (7.32), isoleucine (3.58), valine (2.74), phenylalanine (3.04), tryptophan (0.9), methionine (1.48), lysine (3.39), threonine (2.94), histidine (2.96). Tyrosine (2.12) is the limiting amino acid. The protein quality of the seed was evaluated by in vivo bioassays using weanling male Sprague Dawley rats (50–60 g). The indices of protein quality measured include PER, BV, NPU and TD. There were positive correlation between PER and BV (r = 0.7105), PER and body weight gain (r = 0.9157), PER and nitrogen intake (r = 0.7428). The results showed that T. catappa seed protein has a good pattern of the EAA, is highly digestible, can support growth and positive nitrogen balance and thus has a high dietary protein quality.     

Effect of cottonseed oilcake inclusion on ostrich growth performance and meat chemical composition

This study investigated the effect of replacing dietary soybean oilcake meal with increasing levels of cottonseed oilcake meal (CSOCM) on the growth performance and meat (Iliofibularis muscle) chemical composition of ostriches in order to decrease total feed costs. A total of 105 ostriches were divided into five feeding groups according to the CSOCM inclusion level in the whole diet: Control (0% CSOCM), 3%, 6%, 9% and 12% CSOCM (of the whole diet), and fed with experimental diets from 6 to 13 months of age. As a result of feeding CSOCM, the final live weight and the average daily gain significantly increased in the 12% CSOCM group. The proximate composition, cholesterol content, mineral and fatty acid profile of the meat remained unaffected. Thus CSOCM may be used as an alternative protein source to the more expensive soybean oilcake meal in ostrich nutrition.