Biological Value Protein Research Articles

Biochemical studies of some non-conventional sources of proteins. Part 7. Effect of detoxification treatments on the nutritional quality of apricot kernels.

Detoxification of apricot kernels by soaking in distilled water and ammonium hydroxide for 30 h at 47 degrees C decreased the total protein, non-protein nitrogen, total ash, glucose, sucrose, minerals, non-essential amino acids, polar amino acids, acidic amino acids, aromatic amino acids, antinutritional factors, hydrocyanic acid, tannins and phytic acid. On the other hand, removal of toxic and bitter compounds from apricot kernels increased the relative content of crude fibre, starch, total essential amino acids. Higher in-vitro protein digestibility and biological value was also observed. Generally, the detoxified apricot kernels were nutritionally well balanced. Utilization and incorporation of detoxified apricot kernel flours in food products is completely safe from the toxicity point of view.

Composition of raspberry pomace and its nutritive value for monogastric animals

Raspberry pomace, consisting of seeds, pulp and added rice hulls, is the residue from the pressing of raspberries for juice production. The pomace was evaluated as a feedstuff for pigs by means of chemical analyses, a balance trial with pigs, and balance and growth trials with rats. On average, the pomace contained (dry matter (DM) basis) 11.1% crude fat, 10.0% crude protein, 59.5% total dietary fibre, 46.0% acid detergent fibre, 11.7% lignin, 6.0% cutin, 2.2% acid detergent ash, 26.9% cellulose and 25.13 MJ kg −1 gross energy. Digestibility measurements ( n = 4) with male castrate pigs of 35–55 kg body weight, using diets of 60% complete basal and 40% test material produced the following apparent digestibility values (%) for unmilled and hammer-milled (1.6 mm screen) pomace respectively: DM 10.7 and 20.8 (SEM 1.30); protein 10.6 and 14.7 (SEM 4.83); fat 24.1 and 79.7 (SEM 3.47); energy 7.9 and 28.5 (SEM 1.80). Dry matter digestibility determined with rats showed close agreement with results obtained with pigs. Protein quality was evaluated in tests with rats to measure true protein digestibility (TD) and biological value (BV) for coarse milled (1 mm screen) and fine milled (ball-milled) pomace, either freeze dried or dried at 100°C. Average TD was 33.3% with only small treatment differences. The BV (average 79.3%) was significantly higher for the freezedried, coarse milled pomace (91.0%) than for the pomace subjected to the other three treatments. In a rat growth trial, where pomace replaced barley incrementally, growth rate was not affected at a replacement level of 20%, but it declined consistently thereafter as the level of inclusion increased. Although raspberry pomace has a low content of digestible energy (6.26 MJ kg −1) and digestible protein (1.5%), the results with rats suggest that an inclusion level of up to 20% in a balanced diet would not markedly affect the growth rate of growing finishing pigs.

The apparent digestibility of energy, nitrogen and fibre and the biological value of protein in low- and high-fibre wheat breads

Sixteen 15 kg liveweight entire-male pigs were given either a low-fibre (1.21 g/100 g Neutral detergent fibre, NDF) or a high-fibre (6.38 g 100 g, NDF) wheat bread as their sole source of dietary protein, in a conventional 21-day metabolism study. A glucose/oil supplement which was assumed to be completely absorbed was given with the bread to ensure a high ratio of dietary energy to protein, to allow measurement of biological value (BV). The apparent faecal digestibility of gross energy was significantly (p < 0.001) lower (7.4% units) for pigs given the high-fibre bread as was the apparent digestibility of NDF (24% units lower). The apparent faecal digestibility of total nitrogen was also significantly (p < 0.001) lower for the animals fed the high-fibre bread, but there were no significant differences between the breads for the BV of their protein. The overall mean BV for the breads was 46%. The results indicate a significantly lower digestibility of nutrients and gross energy in breads containing appreciable quantities of wheat bran fibre.

Protein quality of chickpea (Cicer arietenum) with different grades ofCallosobruchus chinensis L. infestation

The chickpea was infested at 20, 40, and 60% levels by Callosobruchus chinensis L. (Bruchids) and its protein quality was evaluated in comparison with that of uninfested chickpea and casein protein. The protein quality parameters used were protein efficiency ratio (PER), net protein utilization (NPU), apparent protein digestibility (APD), true protein digestibility (TPD), biological value (BV) and net protein ratio (NPR). The proximate composition was also determined. The PER, BV, NPU, APD, TPD, NPR and nitrogen retention of casein protein was significantly (p < 0.05) higher than all the pulse proteins. The values for all these proteins for uninfested control were significantly (p < 0.05) higher than the three infested pulse proteins. Within the infestation levels the nitrogen retention, APD, TPD, BV and NPR of the 20 and 40% infestation levels were similar. However, the NPU of proteins at all infestation levels differed significantly (p < 0.05). It may be concluded that, in general, an increase in the infestation levels by bruchids leads to a deterioration in the protein quality of chickpea.

Nutritional evaluation of silage made from the toxic weed parthenium hysterophorus in animals

After ensilation, the toxic Compositae weed Parthenium hysterophorus was devoid of the toxic principle parthenin. Laboratory-scale ensilation indicated that no parthenin was detectable after 5 wk of anaerobic fermentation. For animal feeding studies, silage was made on a large scale from Parthenium mixed with maize or from Parthenium alone. Crossbred bull and buffalo bull calves were fed diets containing the silages, or control diet without silage, for 12 wk. The animals consumed both silages with relish, and body weight gains of silage-fed calves did not differ from those of the controls. The digestibilities of dry matter, fibre and nitrogen-free extract were greater with the control diet, but the biological value of proteins tended to be greater with the silage-containing diets. Haematological studies indicated no significant differences between experimental and control groups in selected parameters, except for a reduction in blood urea nitrogen in the animals fed silage. The possible causes for these biochemical alterations are discussed. Since the nutritive value of Parthenium silage compares favourably with the standard diet, and Parthenium seeds collected from the silage did not germinate, we suggest that ensilation can be used as an additional method in the containment and eradication of these plants, which grow wild in India.

Influence of gastrointestinal microflora on digestibility and biological value of protein in rats.

The influence of the gastrointestinal microflora on the digestibility and biological value of casein was investigated in germ-free (GF) and conventionalized (Cvd) Fischer 344/Yit rats fed an 8% casein diet. There was no significant difference in the true digestibility of casein between GF and Cvd rats, but the apparent digestibility was higher in Cvd than in GF rats. The biological value of casein was significantly higher in GF than in Cvd rats. In the casein diet period, body weight gain was almost the same in GF and Cvd rats, but food intake was significantly greater in Cvd than in GF rats. The excretion of fecal N was similar in GF and in Cvd rats whereas more urinary N was excreted in Cvd than in GF rats. In the protein-free diet period, metabolic fecal N per 100 g of food intake was significantly higher in GF than in Cvd rats, but there was no difference in the excretion of endogenous urinary N per 100 grams of body weight between the GF and Cvd rats. The results indicate that the presence of a gastrointestinal microflora does not influence the true digestibility, but increases the apparent digestibility and decreases the biological value of casein at an 8% level in the diet.

Nutritive value of pumpkin (Cucurbita Pepo Kakai 35) seed products

AbstractThe nutritive value of the pumpkin seed products was evaluated. Isolation of protein eliminated 80% of the phytic acid and 100% of the tannic acid, trypsin inhibitor and flatulence factors. Ethanol treatment during the preparation of the protein concentrate reduced tannic acid by 78% and trypsin inhibitor by 21%, while it had no effect on the phytic acid content. Isoleucine and valine were the first limiting amino acids for meal and protein concentrate, while the sulphur‐containing amino acids and valine were first limiting in pumpkin protein isolate‐I and isolate‐N, respectively. Pumpkin seed products had high levels of crude protein in the range 720–960 g kg−1. In‐vitro protein digestibility and biological value were in the ranges 88–97% and 73–86%, respectively. Both meal and concentrate were rich in minerals (Ca, K, P, Mg, Fe and Zn) while isolates contain remarkable levels of sodium and copper. Pumpkin meal is a good source of the vitamin B group, while a large proportion of these vitamins is lost during the preparation of the protein concentrate and isolates.

Cyanide in garri. 2. Assessment of some aspects of the nutrition, biochemistry and haematology of the rats fed garri containing varying residual cyanide levels

Forty-eight weanling albino rats were used to investigate the dietary implications of the residual cyanide levels of garri using performance, nitrogen balance, relative organ weights, serum and urinary thiocyanate and some haematological variables as the response criteria. The experimental rats showed no outward signs of toxicity. However, rats fed cyanide-containing garri diets had significantly (P ≤ 0.05) slower rates of growth than the controls, and fermentation of cassava improved the utilization of the diets as shown by the enhanced values of feed efficiency, ‘operative’ protein efficiency ratio and biological value with increasing fermentation time. Serum and urinary thiocyanate levels were significantly (P ≤ 0.001) higher in the rats fed garri diets than in the corn starch controls. Regression analysis showed a significant (P ≤ 0.01) positive correlation (r = 0.97) between urinary thiocyanate levels and the residual cyanide content of garri. The haematological variables studied showed no consistent...

Effect of Dietary Fiber on Utilization of Energy and Protein in Chickens.

Cellulose powder, pectin, alginic acid and finely ground rice straw were used as the dietary fiber source. Experimental diets were composed of soybean protein, corn starch, cornoil and some minor ingredients with 10% of above mentioned dietary fibers. A total of 8 colostomized White Leghorn male chickens were forced-fed 70 g/day of the experimental diets for 7 days alternatively so as to make a 4×4 Latin-square design. The amount of fresh feces was significantly higher in the pectin and alginic acid diets, however, water content in the feces was also higher in these diets. Consequently, the dry matter excreted were not different between the treatments, which resulted in no difference of dry matter and energy digestibilities among the diets. Protein digestibility was higher in the cellulose diet and lower in the pectin diet due to the significant difference in fecal nitrogen excretion. Urinary nitrogen was very low in the cellulose diet, and reflecting it biological value of protein was higher in the cellulose diet. Acid detergent fiber was digested by chickens to a small extent, but hemicelluloses seemed to be not digested, because the digestibility of neutral detergent fiber was the same to that of acid detergent fiber.

Comparative study of the nutritive value of casein heated by microwave and conventionally

AbstractThe objective of this study was to compare the net protein utilisation, digestibility and biological value of casein solution heated by microwave or conventionally, ie on an electrically heated plate. Portions (500 ml) of an aqueous solution of casein (100 g litre−1) were heated to a temperature of 80°C and subsequently kept at 80± 5°C for 2 min. The heating times of microwave and conventional heating were the same. Additional portions were subjected to a so‐called abused treatment consisting of repeating the normal microwave or conventional heat treatment three times. Next, the nutritive value of heated and unheated casein was determined in a 10‐day feeding study with Wistar rats. The net protein utilisation, digestibility and biological value of unheated casein were 61.1, 100 and 61%, respectively. Comparable values were obtained for casein heated by microwave or conventionally. These results did not therefore indicate any decrease in nutritive quality of the protein by microwave heating or conventional heating under simulated household conditions.

Nutritional response of growing rats to faba beans (Vicia faba L., minor) and faba bean fractions

The effects of raw faba bean (Vicia faba L., minor) meal (VFM) and its fractions on the growth and nitrogen utilization of rats have been determined in two experiments. Two commercial varieties of VFM were tested, local VFM (409-439 g/kg diet) and Troy VFM (439 g/kg diet). The bean fractions tested were V. faba lectin-depleted protein (VFDP), V. faba lectin (VFL) and V. faba cotyledon residue (VFCR). All diets were supplemented with amino acids to target requirements. Body-weight, body N and lipid contents of rats fed on VFM were reduced significantly in comparison with control rats fed on lactalbumin. This was due, in part, to the lower digestibility of the protein, lipid and dry matter (DM) of VFM diets. As a result, net protein utilization (NPU) and biological value (BV) of faba bean proteins were less than expected. Urine and urea-N outputs of the VFM-fed rats were also elevated in both experiments. Increasing the energy content of local VFM diets led to significantly higher dry body-weight, body N and lipid contents, with the result that the NPU and BV values of the protein also increased. However, the NPU values for VFM-fed rats were still significantly lower than those for the controls in both experiments. In contrast, true N, lipid and DM digestibilities in rats given local VFM were not significantly affected by the difference in the energy content of the diets. The replacement of two-thirds of the lactalbumin in the diet with VFDP (65 g/kg) reduced dry body-weight, N and lipid contents, NPU and BV compared with the control rats, even though N, lipid and DM digestibilities were not significantly different. The nutritional performance of rats fed on lactalbumin-based diets containing 7 g VFL/kg was similar to that of the controls. Similarly, the inclusion of the cotyledon residue (237 g VFCR/kg diet) had no appreciable effect on any of the variables studied. As VFL and VFCR had no antinutritional effects in these rats, it appears that the low nutritional value of VFM for rats (NPU 0.66) results not only from the low digestibility of the bean proteins, but also from disturbances in N metabolism.

Sensory and Nutritional Properties of Cookies Based on Wheat‐Rice‐Soybean Flours Baked in a Microwave Oven

ABSTRACTThree formulas of cookies prepared from 50:45:5 (I), 50:40:10 (II) and 50:35:15% (III) wheat flour, broken rice flour, and defatted soy flour, respectively, baked in a microwave oven (2450 MHz) for 240 sec, were rated as the best of six formulas for flavor and texture by a trained panel. Cookies of formulas I and II were preferred over formula III by a consumer‐type panel. Cookies of all three formulas showed no significant differences in nitrogen balance, apparent biological protein value and apparent net protein utilization. Apparent protein digestibility and protein efficiency ratio were significantly higher in formulas II and III than in formula I.

A novel method for the biological evaluation of protein quality using plasma somatomedin-C (insulin-like growth factor-1) measurement

The objective of the present study was to investigate the validity of plasma somatomedin-C insulin-like Growth Factor-1 (IGF-1) measurement for the evaluation of protein quality. Six sources of protein were evaluated using the conventional methods: protein efficiency ratio (PER), net protein ratio (NPR), relative protein value (RPV), biological value (BV) and protein digestion coefficient (D). Plasma IGF-1 level was also measured on the third day of the feeding period. Plasma levels of IGF-1 ranked the protein sources in the same order as other conventional methods. In addition, values of IGF-1 correlated significantly with the values of PER, NPR, RPV and BV. Protein digestion values correlated poorly with the other methods being used. We conclude that the measurement of plasma IGF-1 is a valid, reliable, easy and rapid method for protein quality evaluation to be used by the food industry and compliance regulatory agencies. Furthermore, this method could be employed for the evaluation of protein quality in infant formulas and for pre-clinical evaluation of enteral formulas.

The influence of selected technological processes on the improvement of rapeseed meal and flour feed quality. Part 2. Effect of hydrothermal treatment and ethanol extraction on the nutritional value of rapeseed products

AbstractIn experiments with rats the effect of feeding flours (dehulled and defatted seeds) and concentrates (flour extracted with ethanol) prepared from non‐heated and heated seeds of low‐glucosinolate rapeseed var. Jantar was studied. Flours and concentrates were fed either as the main protein supplement in cereal‐based diets or as the only protein sources in semi‐synthetic diets; ethanolic extracts were either administered by stomach tube or fed with the diets. Heat treatment of seeds reduced ITC + VOT contents about 27 % and did not affect phenol contents; ethanol extraction removed both ITC + VOT and phenols. Feeding the flours from heated and non‐heated seeds resulted in the increase of thyroid and liver weights as compared with rats from the control group fed on soybean diet. Heat treatment of seeds improved protein digestibility of flours and concentrates and did not modify negative effect of ethanol extract on protein digestibility. Biological value of protein of flours and concentrates was not affected by heat treatment of seeds.Feeding concentrates influenced positively animal growth performance, elimenated hypertrophic effect of the flour on thyroid and liver, increased biological value of protein as compared with flour. Administration of ethanolic extracts containing ITC + VOT and phenols to rats fed on soya‐bean mael diet did not induce hypertrophy of thyroid and liver similar to that observed in rats fed on flours containing these antinutritional substances.

Composition of lipids and proteins of several species of molluscs, marine and terrestrial, from the Adriatic Sea and Serbia

Results of the analysis of lipids, proteins and amino acids as well as calculation of nutritive value parameters in samples of two sea shellfish ( Venus verucosa and Mytilus galloprovincialis), a marine snail ( Monodonta turbinata) and two terrestrial snails ( Helix pomatia and Helix nemoralis) are presented. Lipid analysis revealed a high relative content of cholesterol among the other identified and unidentified sterols. Of significant nutritional importance is a high content of polyunsaturated fatty acids with more than 20 C atoms. Hydrolysed proteins contain all essential amino acids. Calculated from amino acids, pure proteins represent more than 36% and 54% of dry matter of shellfish and snails, respectively. In the case of snails a large difference between crude proteins (determined by Kjeldahl's method) and pure proteins (calculated from amino acid content) indicates the presence of other nitrogen-containing material in considerable quantities. Nutritive values indicate high biological value of proteins in shellfish, very similar to the biological values of other meat sources. Biological value of the snail's protein is lower and similar to soya protein.

Sequence of amino acid limitation in triticale

Nitrogen balance experiments were conducted on growing rats to study the sequence of limitation of amino acids in triticale protein. All essential amino acids were added to a triticale-based diet to adjust their total dietary levels to 110% of the requirement. From this complete supplement, individual amino acids were successively removed and nitrogen balance (NB) and biological value of protein (BV) were measured. Based on the extent of response to removal of amino acids, the sequence of limitation was determined to be lysine, threonine, methionine and valine. The removal of histidine, isoleucine or tryptophan had no effect on NB or BV.

Sequence of amino acid limitation in triticale

Nitrogen balance experiments were conducted on growing rats to study the sequence of limitation of amino acids in triticale protein. All essential amino acids were added to a triticale-based diet to adjust their total dietary levels to 110% of the requirement. From this complete supplement, individual amino acids were successively removed and nitrogen balance (NB) and biological value of protein (BV) were measured. Based on the extent of response to removal of amino acids, the sequence of limitation was estimated to be lysine, threonine, methionine and valine. The removal of histidine, isoleucine or tryptophan had no effect on NB or BV.

The effect of moulds on the nutritional value of wheat

The nutritional value of wheat artificially infested with Penicillium cyclopium, Mucor sp. and Aspergillus flavus was studied in two balance experiments on rats. The samples of ground wheat were sterilized by radiation, inoculated with the suspension of mould spores and incubated for 10 or 30 days at 25°C. The wheat samples and strains of moulds were tested for the production of aflatoxins, cyclopiazonic acid, citrinine, patuline, ochratoxin A and penicillic acid. In addition, the toxicity of wheat extract was tested on chicken embryos. Analyses for mycotoxins and chick embryo toxicity tests were negative. Mould infestation of wheat decreased the fat content and increased fat acidity. The amino acid content was somewhat higher in the inoculated wheat than in a non-inoculated control. The balance experiments showed that the strong infestation of wheat with moulds had no significant effect on the nitrogen digestibility or biological value of protein in rats.

Estimation of optimum amino acid supplements to triticale

Based on the nitrogen balance (NB) data and the efficiency of amino acid utilization, optimum supplements of limiting amino acids (AA) to triticale were calculated and their effect on true N digestibility (TD), biological value of protein (BV) and net protein utilization (NPU) of a triticale-based diet was evaluated. To determine if AA balance must be considered in the calculation of the optimum supplements, the effect of a 20% or 40% excess of essential AA in lysine-, methionine-, threonine- or tryptophan-deficient diets was also studied. The AA excess had no significant effect on NB in diets deficient in lysine, methionine or threonine. However, NB in rats fed on the tryptophan-deficient diet increased as the AA excess increased. BV of the diet containing the optimized supplements of lysine, threonine, methionine and valine was comparable to that of lactalbumin or to the diet supplemented with all essential AA. The deletion of valine from the optimized supplement caused an insignificant decrease in BV. Due to the lower TD, NPU of diets containing the optimized AA supplements was lower than that of the diet containing all essential AA or of the lactalbumin-based diet.

Protein Quality and Iron Bioavailability of Mechanically and Hand-Deboned Turkey Meat Fed to Rats

The protein quality and iron bioavailability of mechanically deboned turkey meat (MDT) and hand-deboned turkey meat (HDT) were determined in rats. The protein, fat, and moisture levels in MDT were similar to those found in HDT. The MDT, however, contained more ash, calcium, and iron than the HDT. The MDT and HDT had similar amino-acid patterns; methionine and cystine were the limiting amino acids for both products. The amino-acid scores were .97 and .98 for MDT and HDT, respectively. The protein efficiency ratio and biological value as well as the values for net protein utilization and nitrogen efficiency for growth for MDT were similar to those for HDT and reference casein (P>.05). The hemoglobin-regeneration efficiency values were 40, 39, and 55%, respectively, for MDT, HDT, and FeSO4 (least significant difference = 12%). The MDT contained more bioavailable iron (7.6 mg of iron per kg of meat or 4.1 mg of iron per 1,000 kcal) than the HDT (4.2 mg/kg or 2.4 mg/1,000 kcal). Mechanically deboning turkey meat did not affect its protein quality, but increased the amount of bioavailable iron.