Effect of heating and fortification with lysine on protein quality of minor millets

The effect of heating and fortification with lysine on the protein quality of five minor millets namely Italian millet (S. Italica), French millet (Panicum miliaceum), Barnyard millet (Echinochloa colona), Kodo millet (Paspalum scrobiculatum) and Little millet (Panicum miliare) was carried out. The N content of the millets ranged from 1.69 to 2.76 per cent. Proximate composition and dietary fibre was estimated. A reduction of 19–25 in TD and increase of 4–18 in BV was observed on auto-claving and both the differences were significant (P<0.05) in all millets. However, heat processing did not have a pronounced effect on DE. Fortification with lysine at 0.6 g/100 DM increased both the BV and NPU. Although both heat processing and lysine fortification improved protein utilisation, the effect of fortification was comparatively more than heating.     

Relationship between dietary fiber levels and protein digestibility in selected foods as determined in rats

Samples of 15 food products and feces obtained by feeding them to rats were analysed for dietary fiber fractions. The food products were added as the sole source of protein in 8% protein diets, making up 8.8–51.6% of the diets. Diets were supplemented with 0.54–5.00% purified cellulose to make them more comparable in total fiber. Fiber analyses of food products revealed that the protein sources provided 0.06–7.27% total dietary fiber. The true protein digestibility in rats was negatively correlated with the total food fiber level (r=–0.69,P<0.01) or with the food cellulose level (r=–0.82,P<0.01) but it was positively correlated (r=+0.81,P<0.01) with the purified cellulose level. No relationship was found between protein digestibility and fiber fermentability. Results indicate that several food fiber fractions and possibly associated substances influenced protein digestibility. Purified cellulose did not have the same physiological behavior as food cellulose from the viewpoint of protein digestibility and fiber fermentability.     

Screening soybean (grain and vegetable) genotypes for nutrients and anti-nutritional factors

Fifty six genotypes of grain-type soybean and 17 genotypes of vegetable-type soybean collections were analyzed for protein and oil content, trypsin inhibitor, and lipoxygenase activities. The protein and oil content ranged from 36.9 to 47.9% and from 13.3 to 23.0% for different accessions in grain- and vegetable-type soybeans, respectively. Trypsin inhibitor and lipoxygenase activities ranged from 22.0 to 47.0 trypsin inhibitor units/mg meal and from 482 to 6265 lipoxygenase units/min/mg meal for grain- and vegetable-type soybeans, respectively. Significant correlations (r=–0.62 and –0.52,P<0.05) were found between protein and oil, and between protein and trypsin inhibitor. A significant positive correlation (r=0.42,P<0.05) was also calculated for oil and lipoxygenase activity. Several genotypes of soybean and vegetable soybean (plant introductions 423905, 417330, 417223, 171451, 200506, 200523, 417124, 227687, 203402, 445842, 203399, 423852, 416771, FC31927, Avoyelles, and Sooty) showed good nutritional potential and may be useful in a breeding program to improve the nutritional quality of soybean. Screening for essential amino acids, fatty acids, and trace minerals for selected genotypes is underway.     

Relationship between amino acid scores and protein quality indices based on rat growth

Protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR) and relative NPR (RNPR) values, and amino acid scores were calculated for 20 food products (casein, casein + Met, beef salami, skim milk, tuna, chicken frankfurters, sausage, heated skim milk, peanut butter, rolled oats, soy isolate, chick peas, pea concentrate, kidney beans, wheat cereal, pinto bean, lentils, rice-wheat gluten cereal, macaroni-cheese, and beef stew). In most cases, PER, RPER, NPR or RNPR ranked the products in the same order and positive correlations among the protein quality methods were highly significant (r=0.98–0.99). Amino acid scores (based on the first limiting amino acid, Lys-Met-Cys, Lys-Met-Cys-Trp or lys-Met-Cys-Trp-Thr) were positively correlated to the PER, RPER, NPR or RNPR data (r=0.61–0.75). Inclusion of the correction for true digestibility of protein improved the correlations between amino acid scores and the indices based on rat growth. The correlations were especially high between Lys-Met-Cys scores (corrected for true digestibility of protein) and PER, RPER, NPR or RNPR (r=0.86–0.91). Inclusion of the correction for true digestibility of individual amino acids did not result in further improvements of the correlations in most cases. It is concluded that adjusting amino acid scores for true digestibility of protein would be sufficient and further correction for digestibility of amino acids would be unnecessary in mixed diets.This paper was presented in part at the 71st annual FASAB meeting, Washington, DC, March 29–April 2, 1987.     

Nutritional evaluation of wheat and maize breads supplemented with a mixture of peanut-chickpea flour

Whole wheat and maize (corn) flours were supplemented with 10, 20 and 30% levels of a 1:1 mixture of peanut and chickpea flours (PCF). Supplementation increased the protein content of the wheat and maize blends by 20–61%. Significant increases in other proximate constituents as well as K, Ca, P, Fe, Zn and Cu levels and lysine were observed. The chemical score (FAO/WHO, 1973) of wheat flour increased from 53 to 72 and that of maize flour from 49 to 71 with 30% PCF. Biological evaluation of wheat breads (baking time = 7 min at 220°C) at 10% protein level and maize breads (baking time = 15 min at 250°C) at 8% protein level in the diet showed significant (P<0.05) improvement in the protein quality of PCF-supplemented breads as judged by gain in body weight, protein efficiency ratio, net protein ratio, net protein utilization, biological value and utilizable protein (NPU% × protein% ÷ 100) content. A supplementation level of 20% was considered adequate to achieve the desired nutritive benefits.     

Water uptake during cooking of dry beans (Phaseolus vulgaris L.)

Water uptake during cooking of ten dry bean (Phaseolus vulgaris L.) varieties was investigated. Water uptake during early stages of cooking was characteristic of the variety. Although the optimal cooking times varied widely (52–85 min), all the beans absorbed similar amounts of water when cooked for their optimal times. Cooking times were significantly correlated with W_{20 min} (r=–0.92) and hardness index (r=0.76) of beans. Most other physical characteristics excepting the surface area of beans were generally unrelated to theW _{20 min},W _opt, and cooking times. No significant correlation was observed between phytate content and cooking times of beans. On cooking for their respective optimal times, all varieties absorbed nearly 1.5 times their weight of water and attained a moisture content of about 65% (wet basis).     

Nutrient composition and anti-nutritional factors in selected vegetable soybean (Glycine Max [L.] Merr.)

The genetic variation in the nutrient composition and anti-nutritional factors of 17 vegetable soybean genotypes were determined and a wide variation in protein %, total phosphorus (TP_i) and available phosphorus (AP) was found among these genotypes. Variations in Ca, K, Fe, Mn, and Cu were also documented. Variation was also found for trypsin inhibitor (TI) activity and Phytate (PA) content. A highly significant and negative correlation (r=–0.533,P<0.01) was observed between TI and total protein. Strong positive correlation (r=0.90) was also found between TP_i and AP. Several genotypes (Sooty, Emperor, Wilson-5, PI 416771, PI 417322) showed good nutritional potential and can be used in the breeding program. High protein %, TP_i, and minerals are desirable qualities for vegetable-type soybeans that make it as food with high nutrient density. Studies on the nutritional evaluation of immature vegetable type soybean seeds at different reproductive stages are also underway.Agricultural Research Station Journal Article Series No. 172. The use of any trade name varieties, and/or vendors does not imply the exclusion of other products or vendors that may also be suitable.     

Fatty acid composition of lipids of Australian oats

A method using methanolic sulphuric acid as transmethylating reagent was developed for determining the fatty acid composition of lipids of oats. The method was optimised for reaction conditions and applied to the determination of the fatty acid composition of lipids of a number of varieties of Australian oats grown in several locations. Thirteen fatty acids were detected with oleic, linoleic and palmitic acids comprising more than 95% of the total fatty acids. Total lipid content of the oats was positively related to the proportion of stearic (r=0·32) and oleic (r=0·81) acids and negatively correlated with the proportion of palmitic (r=−0·64), linoleic (r=−0·39) and linolenic (r=−0·65) acids. Significant positive correlations were found between total lipid content and absolute content of the major fatty acids (r=0·670·98), except for linolenic acid (r=0·12). Environment had significant effects on fatty acid composition, but variety was the controlling factor. The broad sense heritability estimated from individual plot ranged from 69 to 73% and that from the average of three replications and eight locations ranged from 94 to 98% for the major fatty acids. It is possible to improve fatty acid composition of oats by breeding procedures.     

Chemical composition and content of antinutritional factors in Polish cultivars of peas

The seeds of 15 Polish pea varieties contained from 221 to 281 g/kg crude protein with a mean of 240.2±3.5 g/kg dry matter (DM). The weight of 1000 pea seeds, depending on cultivar, ranged from 209.4 to 280.4 g. No interactive effect between the seed mass and the crude protein content was detected. The highest significant negative correlation between weight of seeds and dietary fiber content wasr=−0.815^XX. The content of dietary fiber ranged from 161.5 to 209.9 g/kg with a mean of 187.9±3.8 g/kg. The mean gross energy of seeds was 18.1±0.28 MJ/kg. Amino acid composition of all the cultivars was similar, which was indicated by a similar index of essential amino acids (EAAI) of about 69.7±0.25. Trypsin inhibitor content in seeds was from 2.83 to 7.32 TIU/mg and the content of phytates ranged from 6.32 to 13.36 mg/g DM. The mean content of polyphenols and flavanols in analysed pea cultivars was 0.92 amd 0.46 mg/g, respectively. In the seeds of most cultivars little or no pyrimidine glucosides, i.e. vicine and convicine, were found. The overall mean oligosaccharide content was 64.3±1.8 g/kg, of which α-galactosides were 46.8±2.0 g/kg. The antinutritional factor content was not significantly correlated with protein content. No statistical relationship was found between crude protein and dietary fiber content. It was observed that pea cultivars with higher trypsin inhibitor activity contained significantly less flavanols (r=−0.607^X) and α-galactosides (r=−0.617^X). The varieties with higher seed content of dietary fiber contained the highest amount of α-galactosides (r=0.514^X).     

Individual and combined effects of salinity and waterlogging on Cry1Ac expression and insecticidal efficacy of Bt cotton

Salinity, waterlogging and a combination of both stresses are severe threats to plant growth, development and yield of field-grown cotton (Gossypium hirsutum L.), but their individual or combined effects on insecticidal efficacy of Bacillus thuringiensis (Bt) transgenic cotton and the underlying mechanisms are not well understood. In the present study, two cotton cultivars (33B and SCRC17) containing the Cry1Ac insecticidal protein gene were planted in 10 L pots filled with soil and allowed to grow in a greenhouse. The potted plants were either treated with NaCl (5 mg/g, w/w), waterlogging, or a combination of both stresses at the three true-leaf stage, and levels of total soluble protein, Bt insecticidal protein, gossypol and the control efficacy as indicated by mortality of bollworm larvae were examined at 7-day intervals after stress. Waterlogging and a combination of salinity and waterlogging reduced total protein content by 40–46% and 45–65% and Bt protein content by 38–50% and 45–72% from 7 to 21 days after stress, relative to the non-stressed control, respectively. The control efficacy was significantly reduced by either waterlogging or the combined stress. Regression analysis indicated that Bt protein content was correlated to total soluble protein content (R² = 0.7677*), while Bt cotton efficacy was correlated to Bt protein level (R² = 0.7917**). Salinity reduced Bt protein by 11–22% and total soluble protein by 5.7–7.2% from 7 to 21 days after NaCl stress, but did not result in reduction in control efficacy. It is concluded that reduced bollworm control efficacy under waterlogging or the combined stress could be mainly attributed to the declined levels of Bt protein, which is closely associated with the inhibited nitrogen metabolism by stresses. As one of the secondary compounds that are toxic to pests, increases in gossypol may be involved in maintaining the efficacy when Bt protein level was reduced under salinity.     

The Role of Dextrins in the Stickiness of Bread Crumb made from Pre-Harvest Sprouted Wheat or Flour Containing ExogenousAlpha-Amylase

Dextrins were extracted in water from bread made from pre-harvest sprouted wheat or standard flour supplemented with exogenousalpha-amylases. The dextrins were separated by gel permeation chromatography and the dextrin content (% of crumb weight) determined for different degree of polymerisation (DP) size classes; DP 1–2, DP 3–10, DP 11–50, DP 51–200 and DP >200. There were significant correlations between the dextrin content in each size class and crumb stickiness (r=0·84–0·91, 22 df ). The most significant correlation (r=0·96) was between total dextrin content and crumb stickiness. Addition of dextrins of various DP ranges from various sources to standard flour produced bread with sticky crumb. Again, the degree of stickiness was generally related to the amount of total dextrin in the crumb and not to size distribution of dextrins. In this instance, extensive enzymic hydrolysis of starch was not necessary to produce sticky crumb; the dextrins caused crumb stickiness directly. Addition of dextrins to reconstituted gluten–starch flour produced bread with unexpectedly low dextrin levels and correspondingly low stickiness scores. It is concluded that, to produce sticky crumb, high levels of dextrin of any size are necessary in the crumb; a sticky mass is produced when dextrins dissolve in the excess «free» water that is normally «bound» to starch, gluten and other insoluble components of bread crumb.     

The nutritive value of all-vegetable protein diets based on legume,cereal and tuber in weanling rats

Thirty albino weanling male rats (45–55 g) were divided into five groups of six rats each on the basis of body weight and fed combinations of dehulled brown beans (DBB); parboiled rice (R); and cassava meal (G) which provided 10% protein for 35 days. Casein served as the reference protein. Combinations of DBB (50–80%); with R (18–48%); and G (2%) produced varied effects on body weight, nitrogen (N) intake, N digestibility and retention, BV, liver weight and plasma albumin (P<0.05).The DBB:R:G (70:28:2) blend induced decreases in all the parameters tested except for the BV and PER values. The control group produced digested and retained N, protein efficiency ratio (PER), weight gain and liver weight that were significantly higher than for those of the test diets (P<0.05). These results appear to suggest that starchy foods when blended with legumes at low levels produced good quality protein comparable to casein.     

Starch swelling power and amylose content of triticale and Triticum timopheevii germplasm

Triticale (× Triticosecale Whittmack) and Triticum timopheevii have undergone little selection relative to other grains for quality characters, including starch amylose content. Using starch swelling power (SSP) in water and spectrophotometric analysis of the iodine binding ratio, 247 lines of triticale and 20 lines of T. timopheevii were screened for amylose content. Following this, the expression of the starch-forming protein granule-bound starch synthase (GBSS) in triticale was investigated by SDS-PAGE in the eight highest and eight lowest SSP lines. A strong correlation (R² = 0.8174) was found between iodine binding and SSP. The SSP of T. timopheevii lines ranged from 13.7 to 16.7, indicating an approximate range of amylose content from 28.1 to 33.8%: a small range within typical results from commercial wheat cultivars. The SSP of triticale ranged from 12.5 to 23.6 suggesting amylose content ranged from 12.8 to 35.1%: a much wider range reflecting the contribution of both the wheat and rye genomes. It appeared that expression of GBSS-4A was down-regulated in low amylose lines. Therefore there is significant potential to select for amylose content in triticale to increase quality in both the animal and human feed markets.     

The cocoyam,Xanthosoma sagittifollium,as a potential raw material source for beer brewing

A widely cultivated cocoyam variety,Xanthosoma sagittifollium, was assessed for its suitability for lager beer production, using maltedSorghum vulgare (white variety) for saccharification of the substrate. The three-mash decoction method was used. Results showed that the cocoyam was superior to barley and sorghum as a substrate because of its potentially higher carbohydrate content (71–78%) compared to barley (65%) and sorghum (70–73%). The percentage wort extract was 13.3–14.5° plato compared to 7–12 for barley and 13° for the tuber crop, cassava. The kiln driedXanthosoma sagittifollium gave a dark bager beer with good aroma (68%) and very good flavour (73%) when compared with a commercial lager beer (Monarch) as standard (100%). The alcohol content (4.16% w/v) and the specific gravity (1013) were within the range (4.0–6.4%) and (1011–1019), respectively, specified by the Standard Organization of Nigeria. Although the bitterness value 40 EBU, was higher than the typical range 16–30 EBU, the taste panel indicated this was acceptable. The pH was 4.68 compared with the standard 4.36, while the acidity (as % lactic acid) was 0.36 compared to 0.24 for some commercial products.     

Nutritive quality and energy yield of high oil,opaque-2 and waxy maize hybrids compared to normal maize hybrids

Grain yield, chemical composition, protein quality and digestible energy were measured for 18 maize varieties (opaque-2, high oil, waxy hybrids, normal hybrids) cultivated in Yugoslavia. Protein quality assessment was based on amino acid composition, and true protein digestibility, biological value, net protein utilization and utilizable protein as determined in nitrogen balance experiments with rats. The protein concentration in dry matter varied from 8.63–18.81% while the fat concentration varied from 4.45–16.13%. There were only minor differences in ash and crude fibre, while starch and sugar varied inversely to fat and protein concentration. Lysine levels were approximately 30% higher for the opaque-2 varieties compared with normal maize, while leucine levels were about 30% lower. Yields were extremely high for all varieties with the highest value being 10.3 tonnes/ha. Due to the high yields, protein production/ha was high in range of 822–977 kg. This resulted in high yields of amino acids/ha. Protein utilization was very high in the opaque-2 varieties, which had the highest lysine contents. The biological values were close to 80 in these varieties, whereas they were only 60–65 in the normal maize varieties.     

Chemical composition of kernels from some species ofCucurbitaceae grown in Nigeria

The seeds of lesser-known species —Cucumeropsis mannii, Lagenaria sicceraria varities 1 and 2 andTelfairia occidentalis, ofCucurbitaceae family were studied. The protein content ofC. mannii was 36.1% and the varieties 1 and 2 ofL. sicceraria had 32.1% and 33.3% respectively.Telfairia occidentalis had protein content of 33.2%. The fat contents ofC. mannii, L. Sicceraria var. 1 and 2 andT. occidentalis were 44.4%, 44.6%, 46.9% and 42.3% respectively. The crude fibre content for each of the two varieties ofL. sicceraria was 3.6% andT. occidentalis had 5.5%.Cucumeropsis mannii had the lowest (2.4%) fibre content. The carbohydrate contents forL. Sicceraria var. 2,C. mannii, andT. occidentalis were 12.6%, 13.2% and 14.4% respectively.Lagenaria sicceraria var. 1 had the highest value of carbohydrate (15.8%). The species were relatively rich in potassium and magnesium with range of values of 0.56% to 0.68% and 434 ppm to 444 ppm respectively.Cucumeropsis mannii andLagenaria sicceraria var. 2 had relatively high contents of calcium (117 ppm) and iron (109 ppm) respectively. The kernels of these species exhibited lipase activity.Telfairia occidentalis showed the highest degree of lipase activity.     

Effect of treatment on composition and protein and energy utilization of rice and mung bean by rats

Yellow rice derived from stack-burned unthreshed grains had lower lysine content than white milled rice. Stack burning did not affect energy digestibility in growing rats but decreased true nitrogen digestibility and net protein utilization (NPU). Increasing parboiling time from 20 to 60 min had no adverse effect on energy and protein utilization of parboiled milled rice. Defatting of rice bran-polish with petroleum ether at 50°C had no effect on protein utilization but decreased energy content and utilization. Mechanical dehulling of mung bean (Vigna radiata [L.] Wilczek) reduced fiber content, increased energy and protein digestibility but decreased biological value (BV) and NPU. Toasting and winnowing the bean reduced lysine content, improved digestible energy but decreased BV and NPU. Cooking the bean preparations improved the biological value only in mechanically dehulled bean with resultant higher NPU than that of whole bean.     

Nutritional and Antinutritional Characteristics of Seven South Indian Wild Legumes

Seeds from seven species of wild legumes of the South India were analyzed for proximate composition, mineral profiles, amino acid profiles of total seed protein, in vitro protein digestibility, and certain antinutritional factors to assess their potential as alternative sources of protein crops. The major findings of the study were as follows: crude protein ranged from 20.3 to 35.0%, crude lipid 3.1–9.6%, crude fiber 5.9–12.1%, ash 2.7–5.1%, and carbohydrates 49.2–61.8%. Minerals viz., sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, and manganese occurred in the range 42.9–135.9, 556.2–1639.5, 304.5–572.2, 174.9–686.7, 98.4–947.8, 3.6–16.4, 0.2–1.2, 2.0–30.0, and 1.0–3.9 mg/100 g seed flour, respectively. Profiles of amino acids of total seed proteins detected in the present study revealed that levels of valine, phenylalanine, tyrosine, isoleucine, and histidine of all the seven wild legume seed samples, threonine of Canavalia ensiformis and C. gladiata, leucine of Mucuna pruriens var. pruriens, and lysine of Cassia floribunda and C. obtusifolia were found to be higher than FAO/WHO (1991) requirement pattern. The in vitro protein digestibility of the legumes under study ranged from 63.39 to 83.32%. Antinutritional factors such as total free phenolics ranged from 0.41 to 5.96%, tannins from 0.04 to 0.60%, L-DOPA from 1.34 to 8.37% and trypsin inhibitor activity from 13.48 to 65.43 TIU/mg protein. The detected antinutritional factors probably have little nutritional significance if the seeds are properly processed.     

Effect of nitrogen fertilization on the nutritional quality of wheat variety,Yecora Rojo

The effects of N-fertilization on the nutritional quality of short-straw wheat variety, Yecora Rojo, was studied under sprinkler irrigation system. The fertilizers applied were the conventional N-fertilizer, urea (U) applied as single dose or in three split applications (U-S), and the slow release N-fertilizers, ureaform (UF) (38% N and 20 N), osmocote (OC) with 9 or 14 months longevity and sulphur-coated urea (SCU) with either 17% or 37% dissolution rates in 7 days. These fertilizers were applied at 0 (control), 75, 125, and 175 kg/ha during the 1982–1983 season. Results indicated that at 75 kg/ha there was no significant change in the protein content. At 125 kg/ha, the protein content increased (P<0.05) with urea (applied in three split applications) and OC. At 175 kg/ha, all the fertilizers increased the protein content with the exception of urea (applied as single dose) and UF. Ash content tended to decrease with increasing levels of N, while fat and crude fiber were unaffected. All the fertilizers increased the protein yield (kg/ha), the maximum increase occurring with the slow-release N fertilizers, OC and SCU. Except UF, all the fertilizers decreased the lysine content significantly (P<0.05) in the protein moeity at 175 kg/ha level but lysine percentage in the grain was not reduced. The yield (kg/ha) of individual amino acids including lysine was increased several times at the 175 kg/ha level. P content tended to decrease while Fe and Zn increased with fertilization. Slow-release N-fertilizers, OC and SCU as well as urea (in 3 split applications) appear to have a significant positive effect on the nutritional quality of the grains of wheat variety, Yecora Rojo.     

Nutrient composition and protein quality of minor millets

Nutrient composition of five minor millets produced and consumed in dry land regions and tribal areas of Andhra Pradesh, India, was evaluated. The millets analysed were Italian millet (Setaria Italica), French millet (Panicum miliaceum), Barnyard millet (Echinachloa colona), Kodo millet (Paspalum scrobiculatum) and little millet (Panicum miliare). The nutrients analysed were proximate principles, amino acids, fibre components, calcium, Phosphorus and Iron. Protein and energy were evaluated by true digestability (TD), biological value (BV), net protein utilization (NPU) and digestible energy (DE) in rats. The protein content was higher and lysine content lower, when compared to major millets. Dehusked millets had lower total dietary fibre (TDF) and tannin. The TD of protein ranged between 95.0 to 99.3, whereas the BV was between 48.3 and 56.5. All the millets were poor sources of calcium, phosphorus and iron, with the exception of french millet.