Alpha amylase inhibitors in sorghum (Sorghum bicolor)

Forty varieties of sorghum grown locally and four cereals were screened for inhibitory activity against human salivary amylase. Three varieties of sorghum (IS-22422, Nagi Monadi and Ngd Marnm) had maximum inhibitory activity of 124 units. Among the cereals rice had the lowest inhibitory activity. Amylase inhibitory activity was lost on germination and heating the seeds.     

Studies on α-amylase and trypsin inhibitors in legume seeds using agar diffusion and isoelectric focusing techniques

Amylolytic and tryptic inhibitors of faba bean extracts were determined by an agar diffusion test. The amylolytic inhibitor had protein characters. Furthermore, water-soluble trypsin inhibitors ofCicer arietinum, Lens esculenta, Lupinus termis, Phaseolus vulgaris, Pisum sativum, Trigonella foenum-graecum andVicia faba which were separated by polyacrylamide gel isoelectric focusing (PAGIF) in thin-layers, showed species specific patterns. Negative staining showed 10 bands for French beans, 9 for fenugreek seeds, 8 for lentils and chickpeas, 7 for peas and 6 for faba beans. Lupin seeds were free from trypsin inhibitors. Treatments (soaking, germination and heat processing) of faba beans reduced the number of trypsin inhibitors in PAGIF patterns, less after soaking and germination, but more after roasting and frying. No inhibitors were detected after cooking.     

Biochemistry of Fruit Ripening of Guava (Psidium guajava L.): Compositional and Enzymatic Changes

Changes in chemical composition and the activities of hydrolytic enzymes during four different stages of maturity, viz. mature green (MG), color turning (CT), ripe (R), and overripe (OR), have been studied in guava fruits cv. Banarsi Surkha. Chlorophyll content decreased while carotenoid content increased during ripening. Starch content decreased with concomitant increase in alcohol-soluble sugars. Cellulose, hemicellulose, and lignin also decreased up to ripe stage, while pectin continued to decrease up to OR stage. PG (polygalacturonase) and cellulase exhibited progressive increase in activity throughout ripening, whereas pectin methyl esterase (PME) activity increased up to CT stage and decreased at R stage. The activities of alpha-amylase and beta-amylase decreased significantly with ripening. The most notable metabolic changes occurred between MG and CT stage, implying that for improved postharvest handling, guava fruits may be harvested at CT stage.     

Effect of traditional open sun-drying and solar cabinet drying on carotene content and vitamin A activity of green leafy vegetables

Dried green leafy vegetables constitute a major dietary source of provitamin A carotenoids for people living in semi-arid areas of Tanzania. In the present study, eight vegetable varieties commonly consumed in these areas were either traditionally sun-dried or solar-dried, and the amount of provitamin A carotenoids were determined by HPLC. In the fresh blanched leaves, the contents of -carotene, -carotene, 9-cis--carotene and 13-cis--carotene were in the range of 526–917, 12–39, 80–136 and 16–40 g/g dry matter/basis; dmb, respectively. The average amounts of all-trans--carotene in the leaves after blanching, solar drying and open sun-drying were 662, 502 and 353 g/g dmb, respectively, all significantly different from each other (p <0.001). The average amounts of all-trans--carotene were 21, 15 and 8 g/g dmb (p <0.05) and of 9-cis--carotene 101, 82 and 63 g/g dmb (p <0.05) in the blanched, solar-dried and open sun-dried samples, respectively. Estimation of the amount of retinol equivalents provided by the dried vegetables for preparation of an edible portion of 100 g relish showed that solar-dried vegetables contributed more (between 120–275%) than the recommended level of vitamin A, and on average 43% more retinol equivalents than relishes of open sun-dried vegetables.Thus, it is concluded that the amount of provitamin A-carotenes in traditionally treated vegetables were highly reduced by open sun-drying while solar drying resulted in significantly more retention of the carotenes. All-trans--carotene and 9-cis--carotene were similarly affected as all-trans--carotene by the two drying methods. Consumption of a 100 g portion of solar-dried vegetable relish could provide the recommended daily intake of vitamin A.     

Antinutritional factors in anasazi and other pinto beans (Phaseolus vulgaris L.)

Antinutritional factors of anasazi bean were compared to traditional pinto bean (Phaseolus vulgaris L.). Anasazi beans contained less (p<0.001) soluble and bound condensed tannins compared to pinto beans. No differences (p>0.05) in stachyose and raffinose content were found between the two bean types; verbascose was not detected at all. Significant (p<0.05) differences in lectin content were observed between anasazi and pinto bean. The lectins of anasazi beans were classified as non toxic and those of the pinto beans as toxic types. No differences (p>0.05) in inhibitor activity against human and bovine trypsin and chymotrypsin were found between the two bean types.     

Changes in carbohydrate and nitrogenous components and amylase activities during germination of grain amaranth

Grain amaranth (Amaranthus hypochondriacus), Yercaud local variety, was soaked overnight and germinated for 192 h taking the soaked grains as the zero time (0 h) sample. The changes in the activities of - and -amylases, starch, sugar, protein and lysine contents during germination are reported. Activity of -amylase was high in the 0 h soaked grains, while -amylase activity was high in 72 h germinated grains. The joint action of the amylases resulted in a decrease of starch content from 0 to 192 h in germinated grains and an increase in total sugars during the initial period of germination.Protein nitrogen was found to decrease from 48 h to 192 h accompanied by an increase in free amino acid and non-protein nitrogen contents. Total lysine content was found to be increased by 31% in 24 h germinated grain amaranth. Protein fractionation of raw, soaked and 24 h germinated grain amaranth showed that the distribution of different types of proteins varied during germination of the grains. An increase of water soluble protein content was noticed in 24 h germinated grains.     

Food potentials of some unconventional oilseeds grown in Nigeria — A brief review

A brief review of literature on kernels ofCitrullus andCucumeropsis (egusi melon) species,Telfairia occidentalis (fluted pumpkin),Lagenaria (gourd) species all of Cucurbitaceae family and other oilseeds such asPentaclethra macrophylla (African oil bean),Parkia spp. (African locust bean) both of Mimosaceae family andButyrospermum paradoxum (shea butter) of Sapotaceae family which are grown and widely used as food in Nigeria is presented. The kernels of species of Cucurbitaceae form the bulk of unconventional oilseeds used for food in Nigeria. The nutritional value of some of the kernels and the physicochemical properties and storage stability of the oils obtained from them are discussed. The various consumable forms in which they exist are also described. The problems and prospects of these neglected oilseeds in Nigeria are highlighted.     

Studies on green beans (Phaseolus vulgaris L.)

The phytoalexins produced after the inoculation of green bean pods (Phaseolus vulgaris L.) with the spore suspension of three fungi viz.Fusarium solani, Penicillium patulum andPhytophthora megasperma were studied. Five phytoalexins were isolated and identified as phaseollin, coumestrol, kievitone, phaseollidin and 6--hydroxyphaseollin. Their identity was proved according to m.p., TLC, UV and MS by comparison with authentics. Moreover, the preliminary screening of their antifungal activity was carried out.     

On determination of chitin content in mushrooms

Nitrogen compounds constitute the greatest proportion of the dry weight of mushrooms. These nitrogen compounds are partly protein and partly non-protein. A modified Heneberg-Stohman's method was used to separate non-protein from protein nitrogen, as well as to determine raw fiber content in mushrooms, since the methods used previously for this purpose are time-consuming and complicated. Elemental analysis of crude fiber was performed to confirm the uniformity of isolated products. The content of total crude fiber (fungin) and the proportion of chitin and cellulose in it were determined. The chitin content of 15 species of field grown edible mushrooms was in the range of 1.87–6.93% of total dry mass and 34.51–67.72% of isolated fungin.     

Influence of grain quality,heat, and processing time on the reduction of aflatoxin B1 levels in ‘tuwo’ and ‘ogi’: Two cereal-based products

During the production of tuwo from laboratory-contaminated corn (AFB₁:150 mcg/kg) and sorghum (AFB₁:87.5 mcg/kg) grains, reductions in the aflatoxin-B₁ levels of pastes boiled for 30 min and 60 min were found to be 68.0% and 80.8%, respectively. In the preparation of ogi from contaminated corn and sorghum grains, reductions of about 72.5% and 71.4%, respectively, were obtained after fermentation at ambient conditions. Reconstitution of ogi paste into a porridge (akamu) considerably reduced the AFB level.     

Protein quality and digestibility of new high-lysine barley varieties in growing rats

Four new high-lysine barley mutants, the variety Lysimax, with the high-lysine genelys3a and the mutants mother variety Sultan were grown in a field trial in 1993 at Risø, Denmark. Mutants 609, 1242, 1385 and 1405 yielded in the range of 89 to 98 percent and cv Lysimax yielded 102 percent of cv Sultan (100 percent). One-thousand kernel weights for the mutants were in the range of 87 to 97 percent and cv Lysimax 83 percent of cv Sultan (100 percent). Protein contents of the mutants were slightly higher, in the range of 13.2 to 13.6 percent, than of cv Sultan (13.1 percent) and Lysimax which had a protein content of 12.6 percent. Fat content was higher in Lysimax and in the mutants except for mutant 1385 than in cv Sultan while dietary fibre contents of the barleys were similar. The levels of -glucans and starch were usually lower in Lysimax and in the mutants. The highest lysine levels: 4.6, 4.0 and 3.7 g/16 g N occurred in cv Lysimax and mutants 609 and 1405 compared to 3.3, 3.3 and 3.2 for cv Sultan and mutants 1242 and 1385, respectively. Mutants 609 and 1405 and cv Lysimax also had higher levels of threonine, histidine and valine. The increased lysine contents resulted in large, at most 20 percent, increases in biological value; 88.8, 81.7 and 78.3 percent for cv Lysimax and mutants 609 and 1405 compared to 74.2 percent for cv Sultan. True protein digestibilities and energy digestibilities were slightly lower in Lysimax than in Sultan, 5.3 and 4.3 percentage units, respectively. It is concluded that the development of high-lysine barley varieties is very beneficial for meeting the requirements of indispensable amino acids for humans and monogastric animals. In addition, nitrogen excretion into the environment is drastically reduced due to the higher biological values of the mutants.     

Content of starch and sugars and in vitro digestion of starch by α-amylase in five minor millets

Five varieties of minor millets were studied for their amylose, soluble amylose, amylopectin, soluble amylopectin, reducing sugar, total sugar and starch contents. Pure starch was isolated from each variety and the enzymic degradation of starch by porcine pancreatic -amylase were examined with and without gelatinisation. Gelatinised sample ofEchinochloa frumentacea (var. K2) showed minimal hydrolysis and gelatinised sample ofPanicum miliaceum (var. CO3) showed maximum hydrolysis of starch by porcine pancreatic -amylase. Gelatinised starch was highly susceptible to enzymic digestion when compared to ungelatinised starch. The extent of starch degradation varied from 71 to 85 percent in gelatinised samples and starch degradation in ungelatinised sample varied from 10 to 18 percent.     

Studies on the influence of temperature,relative humidity and microenvironment on the natural fermentation of African oil bean seeds to ‘Ugba’

Studies on the enhancement of the traditional production of Ugba (a protein-rich fermented food) from African oil bean seeds were undertaken by fermenting the bean seeds at different temperatures, relative humidities (RH) and microenvironments. Fermentation was monitored by pH, texture, amino-nitrogen content and the viable cell count of the substrate. The 40 °C, 98% RH or the 130 m high density polyethylene (HDPE) treatment increased the fermentation microflora from ca. 106 CFU/g to ca. 108 CFU/g with high initial changes in pH (5.8–ca. 7.9) and texture (2.0 kg/cm2 to between 1.4 kg/cm2 and 0.9 kg/cm2) in 24 hours. Products with amino-nitrogen contents of between 12.00 mg N/100 g dry matter and 14.00 mg N/100 g dry matter were obtained in 3 days. The cell count of the 30 °C, 80% RH or 70 m treatment increased from 106 CFU/g to ca. 107 CFU/g and the pH increased from 5.8 to about 6.7 with a coincident decrease in the texture value from 2.0 kg/cm2 to about 1.7 kg/cm2 in 24 hours. Products with amino-nitrogen contents between 15.00 mg N/100 g dry matter and 19.2 mg N/100 g dry matter were obtained after 3 days. Changes in the fermentation indicators were not significant at p0.05 (pH and texture) and at p0.01 (amino-nitrogen) after 3 days for the 25 °C, 59.9% RH or 50 m low density polyethylene (LDPE) treatment. Products of fermentation at the combined optimal conditions (80% RH, 35 °C and 70 m HDPE) compared very well with the traditionally fermented products in terms of pH, texture and amino-nitrogen content.     

α and β-galactosidase activities and oligosaccharide content in peanuts

Thirty-three peanut cultivars were examined for their alpha-1,6 and beta-1,4 galactosidase activities and oligosaccharide contents along with proximate compositions. The average moisture, protein, fat, ash, and carbohydrate contents were: 4.9%, 26.6%, 43.1%, 2.3% and 23.1%, respectively. The corresponding coefficients of variation were: 5.2%, 10.1%, 7.2%, 7.8% and 15.7%, respectively. Raffinose and stachyose contents (%) ranged from 0.05 to 0.12 and 0.31 to 0.61, respectively. The specific activity (micromol product/min/mg protein) of crude preparation of alpha-galactosidase for the 33 cultivars ranged from 1.096 to 2.784 for the non-germinated seeds and from not being detected in some samples up to 2.432 for the germinated seeds; the mean values for non-germinated and germinated seeds were: 1.781 and 1.410, respectively. The specific activity of beta-galactosidase ranged from 0.101 to 1.727 in the non-germinated seeds and from not being detected in some samples up to 0.898 in the germinated seeds. Germination decreased the activity of both galactosidases significantly (p < or = 0.05).     

Biological and chemical evaluation of chick pea seed proteins as affected by germination,extraction and α-amylase treatment

The effects of germination, extraction (double extraction with 70% ethanol and water at isoelectric point) and -amylase treatments of chick pea seed flours on crude protein, total carbohydrate, protein efficiency ratio (PER), biological value (BV), true digestibility (TD), net protein utilization (NPU), essential amino acid composition, in-vitro protein digestibility (IVPD) and actual amino acid indices (essential amino acid index or amino acid score) were evaluated. Crude protein content was increased (8–149%), while total carbohydrate was decreased (11–62%) by germination, extraction and -amylase treatments. Alpha-amylase treatment was more efficient in reducing total carbohydrate and increasing the protein content than that of extraction treatment. The protein quality of chick pea flours as measured by PER, BV, TD, NPU, IVPD and corrected amino acid indices (actual amino acid indices×IVPD) was significantly improved by these treatments. The protein quality of germinated--amylase treatment was comparble with casein, while germinated--amylase treaded seeds appeared nutritionally superior to casein. The results indicate that the germinated--amylase and germinated--amylase-extracted treatments could be used successfully as a source of concentrated high quality protein for baby food production. The corrected amino acid indices gave better prediction of PER, BV, TD and NPU (r=93 to 97) than actual amino acid indices (r=45 to 71). PER was highly correlated with corrected amino acid score (r=0.93). The PER could be predicted from the following simple regression equation: PER=–1.827+0.0561×corrected amino acid score.     

Inhibition of α-amylase purified fromOctopus vulgaris Lam. by albumin inhibitors from wheat flour

Octopus -amylase has been purified to homogeneity by single-step affinity chromatography on Sepharose-bound wheat albumin inhibitors. Two electrophoretically distinguishable isoamylases are obtained, both consisting of a single polypeptide chain with molecular weight 45,000. Octopus -amylase is more effectively inhibited by a monomeric than by a dimeric protein inhibitor from wheat. The inhibition is dependent on pH, temperature, and time of preincubation. Properties are compared with those of other animal -amylases.     

Effect of alkaline treatment (‘akanwu’) and supplementary value of corn or crayfish on the protein quality of breadfruit (Treculia Africana)

The effect of treatment and supplementary value of corn (C) or crayfish (CR) on the protein quality of breadfruit (Treculia Africana) flours were studied in eighteen young rats. The 7030 or 701515 (Protein basis) combinations of breadfruit flours and corn or crayfish or both provided 1.6g N/100 g diet for the 35 day study. The addition of akanwu to the cooking water reduced cooking time and crude protein and saved fuel. The addition of akanwu and replacement of CR with C was not beneficial as judged by the parameters tested except for the wt. gain and PER. On the other hand, when crayfish was the only source of supplementary protein (30%) to breadfruit cooked without akanwu there were increases in all parameters tested over those with added akanwu except for the N intake, wt. gain, and PER.These results appear to suggest that addition of akanwu to TA was detrimental to its protein utilization and that TA appears to be an economic source of N in areas where it is a staple. Based on the results of this study, one would suggest that the use of akanwu as a tenderizer should be seriously looked into before further use.     

Changes in β-carotene and ascorbic acid content of fresh amaranth and fenugreek leaves during storage by low cost technique

Leafy vegetables are highly perishable and their shelf life depends on duration and conditions of storage. A low cost storage structure was used to extend the shelf life of amaranth and fenugreek and their quality was evaluated on the basis of retention of -carotene, ascorbic acid and chlorophyll during storage. Losses of -carotene ranged from 46.5 to 85.0% for amaranth and 24.0 to 73.0% for fenugreek depending on duration and conditions of storage. Similarly ascorbic acid retention varied from 9–32% for amaranth and 23–80% for fenugreek. Results showed that the degradation of quality parameters was faster at ambient conditions and packaging of leaves in low density polyethylene bags was beneficial in improving shelf life and nutritive value. Low cost storage structure was similar to low temperature storage for retention of -carotene, ascorbic acid, chlorophyll content and enhancement of shelf life.     

A study to determine an equation of enveloping curve for regional flood peaks by maximum rainfall data

In this paper, Creagers equation and Groups equation are algebraically examined to determine an equation of an enveloping curve for regional flood peaks from the viewpoint of the curve profile. The applicability of a small drainage area with little observed data on flood peak discharge was examined in comparison to specific flood peak discharge calculated by a rational formula using data of maximum rainfall. In the algebraical consideration, the Creagers equation had an extreme value at a drainage area A=1.0 km², and the specific flood peak discharge became a maximum. Flood peak discharge calculated by Groups equation had an extreme value at a drainage area A=6,568 km², and it became a maximum. Except for Hokkaido, in catchment areas not exceeding 1,178 km², Groups curve q _K was closer to the curve q _DAD of specific flood discharge than Creagers curve qc. From the above research results, the Groups equation is applicability better than the Creagers equation, as the drainage area A is 1,178 km² or less.     

Effect of heat treatments on trypsin/chyomotrypsin inhibitor activity of red gram (Cajanus cajan L.)

The application of dry heat to the seeds and meal was not effective in inactivating the trypsin inhibitory activity (TIA) and chymotrypsin inhibitory activity (CIA). Soaking for 24 hours followed by cooking for 20 min was effective in destroying the TIA and CIA.