The nutritive quality of maize-soybean (70:30) tempe flour

The nutritive quality of maize-soybean (70:30) tempe flour manufactured by fermentation withRhizopus oligosporus: Rhizopus orysae (1:1) was determined using weanling rats. Mould fermentation of maize-soybean mixture did not significantly affect its proximate composition. It increased the content of reducing sugars, total acids and aminonitrogen by about 43, 195 and 482 percent, respectively, and decreased phytate content by 46 percent. In vitro iron absorption for maize flour and maize-soybean tempe flour was 2.46 and 5.51 percent, respectively. Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR) for maize-soybean tempe flour and skim-milk diets were 2.71 and 2.96, respectively, for PER, and 3.31 and 3.51, respectively, for NPR. In vivo protein digestibility of the two products was 95.0 and 98.0 percent, respectively.     

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.     

Protein efficiency ratios and net protein ratios of selected protein foods

As a part of a cooperative study initiated to assess bothin vitro andin vivo protein quality methods, the protein efficiency ratio (PER) and net protein ratios (NPR) of 15 different protein sources were determined. Male weanling Sprague-Dawley rats were fed a 10% protein diet. Fourteen-day NPR and relative NPR (RNPR) values and 14- and 28-day PER and relative PER (RPER) values were calculated for each protein source. When protein quality values were expressed relative to ANRC casein, the 14- and 28-day PER data ranked the protein sources essentially in the same order. RPER values of nonfat dried skim milk (unheated) and tuna were more than 100% that of casein; nonfat dried skim milk (heated), chickpeas, and breakfast sausage were between 50 and 70% of that of casein; and pinto beans and rice-wheat gluten cereal did not support substantial growth of the rat. The NPR method did not always rank the protein sources in the same order as the PER method. For the poor quality proteins, RNPR values were much higher than the RPER values; however, the RNPR and RPER values agreed closely for high quality protein sources.A preliminary report of this work was given at the Annual Meeting of the Federation of American Societies for Experimental Biology, Washington, D.C., March 29–April 2, 1987. Fed. Proc. 1987; 46: 889.     

The development and acceptability of lupine (Lupinus mutabilis) products

To ensure the cultivation of the lupine and improve the nutritional state of the Andean population, products have been developed which are enriched with lupine. The high content of bitter alkaloids in the seed of theLupinus mutabilis may be considerably reduced by washing with water (traditional method, ‘Cuzco method’). Drying the grains makes it possible to store them. The lupine with a moisture content of 4 to 8%, can be milled; the flour obtained is slightly yellowish and suitable for panification, where 10 to 40% of the wheat flour may be substituted by lupin. The Protein Efficiency Ratio (PER) of bread was found to be 28% (casein 100%) and was much higher after the enrichment with 10% lupine flour (76%). Lupine based dishes have been well accepted according to a test of acceptability performed with children from 8 to 15 years of age over a three year period.     

Effects of additives on the rheological and mechanical properties of non-conventional fresh handmade tagliatelle

The effects of the following additives on the amaranth (A), quinoa (Q) and oat (O) dough rheological properties and the extruded tagliatelle dough mechanical characteristics were evaluated: carboxymethylcellulose of sodium (CMC), whey protein isolate (WPI), casein (CAS), chitosan (CHIT) and pregelatinized starch (PS). The amaranth, quinoa and oat rheological dough properties and amaranth, quinoa and oat tagliatelle mechanical characteristics were compared to those of their respective controls (ACTRL, QCTRL and OCTRL) and of the SEMOLINA sample. The storage modulus (G′) and loss modulus (G″) values of the quinoa and oat doughs with PS were similar to those of the semolina dough. For all tagliatelle samples, WPI reduced the elastic modulus or Young's modulus towards that of the semolina tagliatelle. Moreover, the additives did not have particular influence on the tenacity with the exception of the amaranth tagliatelle added with WPI.     

Limiting amino acids in raw and processed amaranth grain protein from biological tests

Amino acid supplementation studies with young rats were carried out using raw and processed amaranth grain (A. cruentus) of dark- and cream- or light-colored seeds. The results of various studies repeatedly indicated that threonine is the most limiting amino acid in raw and processed, dark and cream-colored grain. Protein quality as measured either as NPR or PER was improved by threonine addition alone or with other amino acids and decreased liver fat to values similar to those measured with casein. This finding contradicts the reports that state that leucine, determined by chemical score, is the most limiting amino acid. Leucine addition alone or with other amino acids did not improve protein quality. The study confirmed cream-colored grain to be nutritionally superior to dark grain and that properly processed grain, light- or dark-colored, has higher protein quality than raw grain.INCAP Publication I-1525     

Chemical and nutritional evaluation of two amaranth (Amaranthus cruentus)-based infant formulas

The objective of this study was to calculate, prepare and evaluate the Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) of two infant formulas made with amaranth (Amaranthus cruentus). Both formulas were formulated to match a previously developed and tested soy-oats infant formula. No significant differences were found between the three formulas with respect to corrected Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) values. Only the product made with the 1-R fraction of amaranth was found to have a significantly lower P.E.R. than casein.Paper presented at the Annual Convention of the Institute of Food Technologists, Anheim, California, U.S.A., June, 1990.     

True potato seed drying over rice

Summary Toasted polished rice with less than 1% moisture content was used as desiccant for potato seed stored in closed jars. To reduce the moisture content of about 20 g of true potato seed from 11.5% to 4–5%, 30 to 40 g of toasted rice is needed depending on how fast drying is desired. For most crops, 5% seed moisture content is considered by the International Board for Plant Genetic Resources as a safe level for storage. Toasted rice was also used with small lots of tomato, pepper, lettuce, turnip and soya bean seeds to dry them to a safe level for storage. Toasted grains of wheat, maize and soya bean were also used successfully as desiccants, but proved to have less drying capacity than rice.     

The protein quality of lupins (Lupinus mutabilis) alone and in combination with other protein sources

The chemical compositions, of raw and treated lupine flour were determined and compared with other plant protein sources. The protein content in the dry matter was 47.7% in untreated seeds ofLupinus mutabilis and about 56% in debittered seeds. The oil-cake contained 65.3% protein. The amino acid analysis showed that lupine protein is characterized by a low level of S-amino acids, the content of which amounts to only 50% of that of the FAO standard reference pattern. The protein quality was measured using the biological tests PER (Protein Efficiency Ratio), NPU (net protein utilization), and BV (biological value) in rats on diets with and without DL-methionine supplementation. PER determinations gave low values for the non-supplemented lupine proteins (1.34, semi-sweet variety; 1.53, water-extracted seeds; 1.19, oil-cake; 3.09, casein), but the PER's were improved by the addition of 0.2% DL-methionine to the diets (3.05, 2.69, 2.81, respectively). Raw as well as processed lupine protein showed an excellent apparent digestibility (80.0–85.8%; casein, 87.1%). The observed NPU and BV values confirmed the importance of methionine supplementation. The true digestibility of 92% was equivalent to that of casein. The complementation effects of mixing lupine protein with proteins from wheat, oat, barley, rice, maize, potato, quinua or fish were investigated by determination of the PER values of the respective mixtures. Feeding lupine protein with cereal proteins resulted in PER values that exceeded by far those of the proteins fed separately (true complementation). This result was not observed for the mixture of potato and lupine. High quality proteins like quinua and fish protein also showed no complementation effect with lupine protein but did improve the quality of the lupine protein to a great extent. The best results could be obtained with combinations of three different plant proteins, in which lupine protein always contributed one third of total protein. These mixtures resulted in PER values equal to those for casein or other animal proteins and may be applied as an economical way to prevent and combat malnutrition.     

Quality indices of Jew's mallow and spinach during frozen storage

In this study, Jew's mallow and spinach were heat treated and kept frozen, at –18°C, for 3 months. Analysis of some chemical components and enzymatic activities as well as a sensory evaluation were undertaken. At the end of the storage period, blanched spinach showed no PPO (polyphenyloxidase) activity at all, but still contained PO (peroxydase) and LO (lipoxygenase) activities. The untreated spinach stored under the same conditions showed high activities of PO, PPO and LO. The heat treated mallow still contained high enzyme activities which decreased slowly during frozen storage. Statistical analysis of the chemical composition and the sensory evaluation results indicated that heat treatments of mallow caused significant differences in total solids, pH, chlorophylla and total chlorophyll, while frozen storage, of samples of the same treatment for 3 months caused no significant differences in moisture, ash, oxalic acid, pH, chlorophylla and total chlorophyll. No significant differences could be noticed in the overall acceptability between mallow samples mixed with hot water and those mixed in the overall acceptability between mallow samples mixed with hot water and those mixed with a hot 0.1% MgCO₃ solution. Significant differences were found between the heat treated and the untreated mallow. Changes of the chemical composition and the overall acceptability of blanched spinach during frozen storage showed almost the same trend noticed for the Jew's mallow.     

Pseudocereals as alternative sources for high folate content in staple foods

Total folate content was determined in the pseudocereals amaranth (four varieties), quinoa and buckwheat in comparison to four cereal species (eight wheat varieties, four barley varieties, one oat variety, one rye variety). Amaranth and quinoa were found to possess very high total folate contents: in amaranth, total folate ranged from 52.8 to 73.0 and in quinoa it was 132.7 μg/100 g dm, about ten times as much as in wheat. The bran fractions contained on average 124% of total folate, while only 57% on average was present in the flour fractions.     

Effects of pressure treatment of hydrated oat,finger millet and sorghum flours on the quality and nutritional properties of composite wheat breads

Breadmaking achievement using grains alternative to wheat and rye is a challenging task for cereal technologists, since most of the available innovative breads are characterised by poor crumb and crust characteristics, slight flavour and fast staling. To improve texture, mouth-feel, acceptability and shelf-life of breads prepared by using minor and/or under-utilised cereals, gluten and/or polymeric substances that mimic the viscoelastic properties of gluten, are required. Recent studies reported that high hydrostatic pressure (HP) treatment may represent an efficient non-thermal technique to promote the dough structure formation of composite cereal matrices. In the present study the effects of HP on the techno-functional and nutritional properties of oat-, millet-, and sorghum- based breads were evaluated compared to their unpressured- and gluten-added conventionally made counterparts. HP-treated (350 MPa, 10 min) wheat, oat, millet and sorghum batters were added to the bread recipe, replacing 50%, 60% and 40% of untreated wheat flour, respectively. Data from bread analyses revealed non significant physico-chemical impairment, and superior nutritional and sensory profiles in most quality features when HP treatment was applied to dough batters, compared with conventional/gluten-added samples. Specifically, HP breads deserved better sensory scores and exhibited higher antiradical activities despite a reduction in specific volume (wheat and oat) and faster staling kinetics (millet and sorghum) that were explicit in some composite samples.     

Development,nutritive content and shelf life of home processed supplementary foods

Four low cost supplements containing whole wheat, pearl millet, bengal gram, green gram grain and amaranth leaves employing roasting and malting methods were developed. Nutritional evaluation showed that chemical composition of developed supplements was within the range prescribed for processed supplements and could meet satisfactorily one third requirements of protein, energy, iron and calcium for young children. Developed supplements were stored in three packings, polythene bags, tins with lids, glass bottle with lids (each 1 kg capacity, under ambient temperature (24–32°C) and RH (70–80%) for a period of 30 days and analysed for moisture, peroxide value, fat acidity and alcoholic acidity. Stored samples were also evaluated organoleptically. The values of moisture, peroxide value, fat acidity and alcoholic acidity of stored samples were within the range of prescribed specifications for processed supplements. Storage of supplements for 30 days resulted in non-significant changes in organoleptic traits except for taste and aroma of bajra based supplements on 20th and 30th day of storage. In spite of these variations, all the supplements were found to be acceptable till 30th day of storage.     

Pasting,thermal and rheological properties of octenylsuccinylate modified starches from diverse small granule starches differing in amylose content

Waxy maize (a standard starch of normal granule size) and five small granule starches from different botanical sources (rice, wheat B type, oat, quinoa and amaranth) were subjected to 2-octenyl-1-succinic anhydride (OSA) modification. Changes of pasting, gel texture, thermal and rheological properties were investigated. Different small granule starches showed quite different property changes after OSA modification. Pasting viscosity was generally increased in OSA starches, among which OSA oat starch had notably high peak and breakdown viscosity but low setback viscosity. Gel hardness of rice, wheat B type, oat and quinoa starches was reduced by OSA treatment, whereas that of waxy maize and amaranth starches was increased. Amylose content was considered to be the major factor influencing pasting, gel and thermal property of OSA starches. Esterification increased pseudoplastic flow behavior of all starches, while OSA oat starch uniquely had reduced flow consistency coefficient. The dynamic rheological properties were also changed differentially among OSA starches. Viscoelastic properties of rice, wheat B type, oat and quinoa starches were increased after OSA treatment, whereas those of waxy maize and amaranth starches were decreased. This study showed that diverse functionalities from OSA small granule starches may fulfil different demands in product development.     

Effects of altitude above sea level on the cooking time and nutritional value of common beans

The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of theOstua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value,which included Net Protein Ratio (NPR), Protein Effciency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient T, as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to a lower protein quality, with respect to altitude, the effect of which was more obvious in the apparent protein digestibility values. Undercooking or overcooking at one location influenced protein quality values. The extended cooking time of beans at high altitudes, has important economic and environmental implications, since significant amounts of wood have to be used.     

Protein quality of developed home made weaning foods

Home made weaning foods developed from locally available foods like bajra, barley, green gram (Vigna radiata L.), amaranth grain (Amaranthus sp.) and jaggery using household technologies like roasting and malting had a PER ranging from 2.04 to 2.13, BV 79.56 to 80.68, NPU 66.75 to 67.86, NPR 2.13 to 2.76 and PRE 34.18 to 44.18. The values were comparable to that of cerelac—a commercial weaning food.     

Glycemic index of grain amaranth, wheat and rice in NIDDM subjects

Glycemic index of grain amaranth, wheat and rice preparations was studied in noninsulin dependent diabetic subjects. Diets containing 50 g carbohydrate equivalent were given and post-prandial blood glucose estimated at different intervals. Glycemic index calculated for different experimental diets showed that GI of amaranth-wheat composite flour diet (25∶75) was the least (65.6%) followed by wheat diet (65.7%), rice diet (69.2%), amaranth-wheat flour 50∶50 (75.5%), and popped amaranth in milk (97.3%). Therefore 25∶75 combination of amaranth and wheat, wheat and rice can be considered low GI food, 50∶50 grain amaranth and wheat medium GI food and popped amaranth and milk combination high GI food.     

Nutritive value evaluated on rats of new cultivars of common beans (Phaseolus vulgaris) released in Chile

Five new cultivars of common beans (Phaseolus vulgaris) recently released were analyzed for their proximate chemical composition and protein biological quality. The crude protein content in these cultivars ranged from 21.9 percent in cultivar Arroz 3 to 26.9 percent in cultivar Tórtola Diana (dry matter basis). Rats fed cultivar Tórtola INIA gained more weight, had a higher protein intake and registered higher PER and NPR than Tórtola corriente. On the other hand, rats consuming cultivars Arroz 3 and Fleetwood had lower weight gain, lower protein intake and lower PER and NPR than cultivar Coscorrón corriente. However, all these cultivars have a relatively good protein value as compared to other plant protein sources.