Biological response to different diets of fermented and unfermented mixtures of flour and cereal brans

The objective of this study was to biologically evaluate eight mixtures of flour and brans prepared with non‐conventional foods popularly denominated ‘multimixtures’, which differed from each other in terms of type of bran (wheat or rice), presence or absence of cassava leaf powder and submission or non‐submission to a solid‐state fermentation with Saccharomyces cerevisiae for 6 h/30 °C, utilising female Wistar/UFPEL rats. Biological indices determined were food efficiency ratio (FER), protein efficiency ratio (PER), net protein efficiency ratio (NPR) and in vivo digestibility. Liver, spleen and kidney specimens were collected at the end of the experiment. In vivo digestibility of diets containing multimixtures formulated with wheat bran was superior to diets containing rice bran, presenting values from 76.5% to 82.8%, which corresponds to up to 85% of casein digestibility. The results allowed the conclusion that fermentation tended to improve food efficiency, but did not influence in vivo digestibility.     

水解反应对菜籽蛋白生物利用度的影响研究

研究了菜籽蛋白经酶解后在生物体内的生物利用,考察了水解度对菜籽蛋白生物利用度的影响。将雄性SD大鼠64只,随机分成8组,即无氮组、酪蛋白组、菜籽蛋白组、水解度(DH)为4%、8%、12%、16%、20%的水解组,每组8只。大鼠在膳食平衡3 d之后,开始进行代谢试验,测其真消化率、表观消化率、净蛋白利用率、生物价指标。连续饲喂21 d之后,记录SD大鼠的体重变化和日粮消耗量,计算蛋白功效比值和净蛋白比。结果表明,真消化率、表观消化率、蛋白功效比值、净蛋白比和SD大鼠体重随水解度的增大有降低的趋势,DH 4%组与菜籽蛋白组相比无显著差异(P0.05)。菜籽蛋白水解之后的净利用率要高于未水解的蛋白,但差异不显著(P0.05)。与菜籽蛋白组相比,DH 4%组的生物价就已经有了显著的提高(P0.05);而与水解度更高的组相比,DH 4%组生物价无显著变化(P0.05)。综合考虑,说明DH 4%组具有较高的生物利用度,是适合人类食用的优质蛋白。     

Physical Properties of Dietary Fiber and Binding of Mutagens

Some characteristics of dietary fiber that may contribute to the epidemiology of intestinal disease including colon cancer were investigated. Soft white wheat bran (AACC), hard red wheat bran (AACC), corn bran, and cellulose were tested for their ion exchange capacity and ability to bind mutagens (benzopyrene, 2-amino anthracene (2-AA), and mutagens extracted from fried ground beef. The wheat brans had the highest ion exchange capacity and were effective in binding the 2-AA. Benzopyrene and the fried ground beef mutagens were not effectively bound by fibers. The results suggest that dietary fibers may modify the levels of some intestinal mutagens, but may be ineffective for fried ground beef mutagens.     

Effects of Fiber Type and Level on Mineral Excretion, Transit Time, and Intestinal Histology

The effects of various fibers on transit time, jejunal histology, and fecal excretion of nitrogen and five trace elements were determined in rats. Cellulose, microcrystalline cellulose, pectin, soy fiber, and wheat bran were fed at l%, 5%, lo%, and 15% dietary levels based on neutral detergent fiber (NDF) analysis. Transit times varied significantly for both fiber type (P < 0.01) and level (P < 0.05). Jejunal histology showed that macrovilli surface area increased with longer exposure to the fiber and with a higher level fed. There was no effect of fiber level on mineral excretion and only a few general trends with regard to effects of fiber type. It is suggested that dietary fiber fractions other than those determined by NDF analysis influence cation exchange of minerals in the gut.     

Biological utilization of insect infested wheat stored in different storage structures

Wheat (Triticum aestivum) was stored in jute bag, peru, metal bin and polyethylene bag for 6 months. Infested wheat was fed to the rats for 40 days. Effect of incorporation of uninfested and infested wheat stored in different storage structure on feed intake, weight gain, feed efficiency ratio (FER), protein efficiency ratio (PER), biological value (BV), true protein digestibility (TPD), net protein utilization (NPU), net protein ratio (NPR) and weight of liver, kidney and spleen was observed. Inclusion of insect infested wheat stored in different storage structure had significant (P > 0.05) effect on the biological utilization of wheat protein. Diets prepared from wheat stored in jute bag and peru had significantly higher insect infestation which resulted in lower values for feed intake, weight gain, FER, PER, BV, TPD, NPU, NPR. Weight of liver, kidney and spleen also decreased as compared to the control diets and the diets prepared from wheat stored in metal bin and polyethylene bags.     

NUTRITIONAL QUALITY OF SURIMI POWDER FROM THREADFIN BREAM

Threadfin bream (Nemipterus japonicus) surimi was dried to produce surimi powder with a moisture content of about 5%. The surimi powder contained 72% protein and 20% carbohydrate. Although the protein content was lower than for dried fish flesh, the nutritional quality of surimi powder was higher than for dried fish flesh and casein. The protein efficiency ratio (PER), net protein ratio (NPR), apparent digestibility and true digestibility of surimi powder were 3.42, 5.37, 92.1 and 95.3, respectively, while for fish flesh they were 3.21, 5.20, 90.7 and 94.4, respectively. Freeze-dried surimi powder had superior nutritional properties compared to oven-dried method.     

Comparative studies of some local oil seeds and seed cakes

A survey on the chemical constituents (protein, fat, carbohydrates, ash, fibre, calcium, phosphorus, iron) of 4 seeds and their cakes was done. These seeds are safflower seed (Carthamus tinctorius variety Giza 1), sunflower seeds (Helianthus annuus variety Giza 1), linseeds (Linum usitatissimum variety Giza 4) and imported rape seeds (Brassica napus Erglue). Caloric value of these seeds and seed cakes was calculated, PER, NPR and NPU were determined. No great variation was found with respect to the moisture content. The 4 seeds are rich in protein and fat. The ash content varies from (5.11 ± 0.26)% to (3.17 ± 0.13)%. The fiber content was low in both safflower and sunflower seeds and higher in both linseeds and rape seeds. The caloric values of the different seeds were very close. The seeds were found to be rich in phosphorus and low in calcium and contain considerable amounts of iron. The average PER values were 1.51, 1.61, 1.59, 1.84 and 2.50 for safflower seed cake, sunflower seed cake, linseed cake, rape seed cake and casein diet respectively. The average NPR was 3.11, 2.84, 2.84, 3.05 and 3.53 for safflower seed cake, sunflower seed cake, linseed cake, rape seed cake and casein respectively. The NPU values of the seed meals were 48.5, 49.3, 47.4 and 93.6 compared with 67.8 for casein. Using the different criteria (PER, NPR and NPU), it was clear that the protein quality of sunflower seed is very close to that of the linseed. Comparing the protein quality of safflower seed with those of both sunflower and linseed, NPU was in the same range, while PER was somewhat lower and NPR was higher than those of safflower and sunflower seed.     

Effect of Dietary Fiber Constituents on the In Vitro Digestibility of Casein

The in vitro digestibility of casein was substantially decreased by food type gums in the following order: karaya > ghatti > tragacanth > guar > locust bean. Extent of reduction of protein digestibility appeared to be related to the structure of the gum (degree of branching and extent of ionization). The fiber constituents, holocellulose, lignin, apple pectin, and the residues from protease predigested wheat bran and great northern bean, when present, significantly (P < 0.05) reduced casein digestibility. Gel filtration of the soluble portion from the casein hydrolysates containing pectin and bran or bean residues showed the presence of peptide fractions of larger molecular weight than those in a hydrolysate from the casein control. Results supported the hypothesis that dietary fiber constituents may reduce protein digestibility and increase nitrogen excretion through ionic interaction, matrix restriction, and modification of filtration characteristics by the fiber components tested.     

EVALUATION OF THE NUTRITIONAL QUALITY OF NONTOXIC KERNEL FLOUR FROM JATROPHA CURCAS L. IN RATS

ABSTRACT

The origin of Jatropha curcas L. is in Central America, probably Mexico, although it is also distributed in South America, Africa and Asia. In Mexico, it grows as nontoxic and toxic J. curcas genotypes. In this work, the protein quality including protein efficiency ratio (PER), net protein ratio (NPR) and true digestibility (TD) of nontoxic genotype defatted flour was assessed using Wistar rats. The probed diets contained flour (3), flour‐lysine, 1% (4), flour‐phytase, 500 FTU (5) and two control diets: nitrogen‐free (1) and casein (2). The rats were fed for 28 days. The PER (1.37, 1.77 and 1.61) and NPR (1.80, 2.29 and 2.12) obtained values for diets (3.4 and 5) were lower than those obtained for casein (2.07 and 2.46), respectively. No statistical differences were found in TD.

PRACTICAL APPLICATIONS

Jatropha curcas defatted flour may be used in the food industry for the development of diets for human and animal consumption. Besides achieving fortification of foods that are made from wheat, which has a low protein content, with the addition of Jatropha meal, these foods will improve the protein quality of many food products.     

Nutritional Properties and Metabolic Studies of Acylated Beef Heart Myofibrillar Proteins

Beef heart myofibrils were acylated with several concentrations of acetic (AA) and succinic (SA) anhydride, and digestibility and utilization of the myofibrillar proteins were determined. Results for in vitro hydrolysis of the untreated and acylated proteins varied, depending on the enzyme(s) used in the analysis. Rat protein efficiency ratios and net protein ratios for untreated (PER = 2.83, NPR = 116) and acetylked (PER = 2.55, NPR = 110) proteins were greater than for casein (PER = 2.50, NPR = 100), whereas values for succinylated proteins (PER = 2.36, NPR = 87) were less than for casein. Most of the radioactivity recovered after 24 hr from rats fed ¹⁴C-acylated myofibrillar proteins was in expired CO₂; 62.8% for ¹⁴C-acetylated and 45.8% for ¹⁴C-succinylated proteins. Rats acclimated to an acylated protein diet for 28 days showed improved metabolism of ¹⁴C-acetylated protein and decreased metabolism of ¹⁴C-succinylated proteins; 75.7% and 38.1% recovery as expired CO₂, respectively.     

Study on the Complementation of Two Proteins of Low Quality: Black Bean (Phaseolus vulgaris) and Sesame (Sesamun incdicum L.).

In order to determine the complementary potential of black bean and sesame proteins, female rats were fed diets with 10% protein from black bean, sesame or combinations of these. Data showed that diets with these proteins combined had better quality than either protein alone. Maximum protein quality was observed when the two protein sources were mixed in a 1:l (w/w) ratio. This mixturn had PER and NPR values 2 and 5 times higher, respectively, than those of the black bean protein alone and 61 and 71% of the values of PER and NPR, respectively, obtained with a casein diet. Also, there was no alteration of serum or liver lipids.     

Nutritional quality of complementary food prepared from unmalted and malted maize fortified with cowpea using extrusion cooking

The nutritional quality of extruded unmalted or malted maize fortified with cowpea as complementary food was assessed based on its proximate analysis, amino acid composition and results from rat feeding with the blends. Results indicated a slight decrease and increase in protein content due to malting and extrusion respectively. The changes in fat, crude fibre and ash content were not significant. The blends were a good source of energy, ranging from 1831 to 2045 kJ per 100 g. Extrusion significantly increased the amino acid content of the blends, while malting had a varied effect on each of the amino acids. There was no significant difference in the protein efficiency ratio (PER), net protein ratio (NPR) and weight gain of rats fed the blends when compared with the control (casein diet). The present study shows that malting improved the nutritional quality of the blends. Rats fed the casein diet had higher values for total digestibility (TD) and net protein utilisation (NPU). There was no significant difference (P > 0.05) in the internal organ weights of rats fed all blends except the protein‐free diet. © 2000 Society of Chemical Industry     

Hepatic purine enzymes and uric acid excretion as indicators of protein quality in chicks fed graded L-lysine diets

Indicators of protein metabolism may be used in protein quality determination since they respond very rapidly to the quantity and quality of the protein consumed. Accordingly, in this study, the uric acid excretion and the hepatic activity of the purine enzymes nucleoside phosphorylase (EC 2.4.2.1) and xanthine dehydrogenase (EC 1.2.3.7) measured in chickens were correlated with the results obtained with two traditional methods used in protein quality evaluation such as protein efficiency ratio (PER) and net protein ratio (NPR). Data were obtained using diets prepared with single amino acid mixtures which provided 0, 5, 10, 25, 50 and 100% of the chicken lysine requirements. These mixtures provided a gradual increase in protein quality and were also tested in rats. The high correlation coefficients obtained when the results of PER or NPR were compared with the uric acid excretion or with the activities of both enzymes, suggest a practical use of these indicators in protein quality evaluation. This possibility was supported by the fact that the PER and NPR values of the mixtures measured in the chickens were similar to those obtained with rats with correlation coefficients between both species higher than 0.9.     

Effects of fumarate on ruminal ammonia accumulation and fiber digestion in vitro and nutrient utilization in dairy does

The objective of this study was to evaluate effects of fumarate on ruminal ammonia accumulation and fiber digestion in vitro and on feed intake and nutrient utilization in dairy does. Batch cultures of mixed rumen microorganisms were used to study effects of different concentrations of fumarate on fermentation with various N sources (ammonia as ammonium bicarbonate, casein amino acids, casein peptides, gelatin peptides) and feeds (bermudagrass hay, mixed diet of 60% bermudagrass hay plus 40% concentrate) for 6 and 24 h, respectively. Substrates were grouped into pairs for separate incubations. Monosodium fumarate was added to incubation tubes to achieve final concentrations of 0, 5, and 10 mM fumarate. More ammonia accumulated at the end of incubation with added ammonium bicarbonate. Ammonia concentration was higher for peptide compared with amino acid incubation, and for casein peptide compared with gelatin peptide. Addition of fumarate linearly decreased ammonia for all N sources and for feed substrates. For all substrate types, fumarate treatment increased acetate, propionate, and total volatile fatty acids (VFA), decreased acetate to propionate ratio, and tended to reduce branched-chain VFA. Digestion of feed neutral detergent fiber (NDF) by rumen microorganisms was improved by fumarate along with elevated endoglucanase and xylanase activities. In an animal metabolism experiment, 8 dairy does (4 per treatment) were used in a completely randomized design for 21 d. Does were fed a hay plus concentrate diet without (control) or with fumarate (6 g/head per day) supplementation to determine feed intake, whole-tract nutrient digestibility, and N utilization. Fumarate treatment did not affect weight change or feed intake but increased whole-tract digestion of gross energy, crude protein, and cellulose. Digested N was increased by fumarate supplementation; however, N retention was unaffected. Plasma glucose concentration was elevated with fumarate but urea N concentration remained unchanged. Fumarate addition had significant effects on rumen microbial fermentation by decreasing ammonia and branched-chain VFA, and by increasing acetate and propionate, and NDF digestion. These effects were reflected in the improvement in whole-tract gross energy, crude protein, and cellulose digestion and elevated plasma glucose concentration when dairy does were supplemented with fumarate.     

Effects of Particle Size and Breadmaking on Physiological Responses of Meal-Fed Rats to AACC Wheat Bran

Adult rats were meal-fed diets containing 20% AACC certified hard red spring wheat bran (as received, ground, incorporated into bread) for 12 days to determine the short-term processing-induced effects on gastrointestinal function and serum lipids. Fecal nitrogen, fecal fat, transit time and serum triglyceride levels were influenced by the consumption of wheat bran, but not by the grinding or breadmaking procedures. Reduction of bran particle size decreased dietary hemicellulose and reduced fecal bulk as well as defecation frequency. Incorporating bran into bread reduced dietary neutral detergent fiber (NDF), reduced intestinal passage rate of the ground wheat bran and decreased degradation of dietary fiber components in the unground wheat bran.     

Fiber Constituents and Fibrous Food Residue Effects on the In Vitro Enzymatic Digestion of Protein

In vitro digestibility of casein was significantly (P < 0.05) reduced as the fiber weight-to-protein weight ratio increased from 0.0:1.0 to 1.0:1.0 for isolated fiber constituents and fibrous food residues. For casein digestibility in the presence of fiber constituents, the reduction ranked in the following order: karaya gum > xylan > pectin > lignin > holocellulose. The order of reduction by fibrous food residues ranked as follows: kernel corn > blackeye pea > broccoli > brown rice > wheat bran. Gel filtration profiles of casein hydrolysates were generally not affected by the fiber constituents whereas significant alterations to greater molecular weight peptides occurred in the presence of food residues. The data supported the interaction of dietary fiber components by interference of the enzyme-substrate complex formation in proteolytic digestion.     

米糠蛋白改善大鼠脂质代谢作用及机制研究

为了讨论米糠蛋白对高脂饮食状态大鼠脂质代谢的影响及作用机制。试验设计酪蛋白组（CAS,对照组）、米糠蛋白组（RBP）、糙米蛋白组（BRP）和大米蛋白组（WRP）等4组,饲喂大鼠分别添加了质量分数20%酪蛋白、15%酪蛋白+5%米糠蛋白、15%酪蛋白+5%糙米蛋白和15%酪蛋白+5%大米蛋白的高胆固醇饲料3周。实验测定大鼠血清总胆固醇（TC）水平、甘油三酯（TG）浓度以及肝脏TC、TG和总脂质的含量,并收集了实验后期3 d的粪便,测定其总胆汁酸和中性固醇的排泄量。采用体外模拟人体胃肠消化道环境试验,测定CAS、RBP、BRP及WRP对胶束溶解度的抑制率和不同浓度RBP的胆汁酸结合能力。结果显示,高纯度米糠蛋白与酪蛋白和其他蛋白组相比较能明显降低高胆固醇饲喂大鼠的血清TC（P<0.05）以及动脉粥样硬化指数（P<0.05）,肝脏TC水平显著降低（P<0.05）,粪便中总胆汁酸排泄量显著增加（P<0.05）。体外实验结果表明,米糠蛋白能与胆汁酸相结合,显著抑制了胆固醇胶束溶解度（P<0.05）。综上所述,米糠蛋白在体内与胆汁酸相结合,抑制其在肠道的吸收,增加其粪便中的排泄量,最后达到降血脂的作用。     

Effect of dietary fish oil on fatty acid composition, lipid oxidation and sensory property of chicken frankfurters during storage

Broilers fed with three levels of fish oil (0, 2 and 4%) for 6 weeks were used in the manufacture of chicken frankfurters. The meat samples were vacuum-packed and stored at 0°C for 0, 10, 20 and 30 days. Cooking yield, proximate and fatty acid composition, lipid oxidation, microbial and sensory properties of the meat products were measured. Cooking yield, moisture, fat, protein, ash and cholesterol contents of frankfurters were not affected (P>0.05) by levels of dietary fish oil. Frankfurters processed from chickens fed diets enriched with 2 and 4% of supplemental fish oil had a higher (P<0.05) level of n-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid), but had a lower level of n-6 fatty acids (P<0.05) than the controls (0% fish oil). TBA values and pH values of meat samples were not affected (P>0.05) by levels of supplemental fish oil in the diets, however, pH values of the vacuum-packaged chicken frankfurters decreased (P<0.05) as the storage time increased. No differences (P>0.05) in total anaerobic plate counts were observed among the fish oil treatments during storage. Supplementation of 2 and 4% fish oil in the diets did not increase (P>0.05) the intensity of fishy flavor in chicken frankfurters.     

Determination of Neutral Detergent Fiber in Breakfast Cereals: Pentose, Hemicellulose, Cellulose and Lignin Content

Cereals are often promoted as important sources of dietary fiber. Ninety one breakfast cereals available in Canada and four unprocessed wheat brans were therefore analyzed for neutral detergent fiber (NDF) after rapid digestion with α-amylase from porcine pancreas. Many breakfast cereals contained less than 5% NDF. Wheat cereals contained 5–30% NDF, oat cereals contained 5% NDF, and corn and rice contained little NDF. Cereal NDF was predominantly hemicellulose (pentosans); pentose sugars liberated under hydrolysis represented up to 15% of processed bran cereals and 20–25% of unprocessed bran.     

Effect of the Addition of Different Dietary Fiber and Edible Cereal Bran Sources on the Baking and Sensory Characteristics of Cupcakes

The effect of successively replacing (10%, 20%, and 30%) wheat flour with dietary fiber (DF) from wheat, oat, barley, and maize or cereal bran (CB) from wheat, oat, and rice on cake batter, final cake quality parameters, as well as on product shelf-life was studied. Batter viscosity (control, 2.96; wheat fiber 30%, 20.21; rice bran 10%, 0.47 Pa sⁿ), cake-specific volume (control, 2.27; wheat fiber 20%, 2.83; rice bran 30%, 1.94 cm³/g), porosity (control, 0.75; wheat fiber 30%, 0.81; rice bran 30%, 0.69), and crumb moisture content (control, 20.07%,; wheat fiber 30%, 26.45%; oat bran 30%, 13.89%) increased significantly (P < 0.05) with DF addition but decreased with CB addition. Addition of DF resulted in softer crumb texture (Control, 4.20 N; wheat fiber 20%, 3.19 N), while CB addition increased crumb firmness (rice bran 30%, 10.84 N), respectively. Minor differences were observed in the crumb and crust color of the DF cakes with respect to the control. Addition of CB decreased the L values of crumb color significantly and the decrease increased with increased level of CB incorporation. DF addition led to cakes with greater acceptance by panelists than CB addition, similar to the control. DF cakes stored in polyethylene bags at 25 °C and 60% relative humidity for 6 days showed delayed moisture loss and lower firmness compared to CB cakes. The optimal level of incorporation based both on the objective and sensory characteristics results was found 20% for DF and 10% for CB, respectively. Concluding, by incorporating DF or CB properly, cakes with improved nutritional value can be manufactured.