Dietary fibre has been shown to have important health implications in the prevention of risks of chronic diseases. The objective of the present study was to determine the potential health benefits of legumes as a good source of dietary fibre. Six to ten local legumes were studied as follows: cowpeas, mung beans, pole sitao, chickpeas, green peas, groundnuts, pigeon peas, kidney beans, lima beans and soyabeans. The following studies were conducted: (a) mineral availability, in vitro; (b) glycaemic index (GI) in non-diabetic and diabetic human subjects; (c) the cholesterollowering effect in human subjects with moderately raised serum cholesterol levels. The highest Fe availability among legumes was for lima beans (9·5 (SEM 0·1)) while for Zn and Ca, the highest availability was for kidney beans (49·3 (SEM 4·5)) and pigeon peas (75·1 (SEM 7·1)), respectively. Groundnuts have the lowest Fe (1·3 (SEM 1·1)), Zn (7·9 (SEM 1·3)) and Ca (14·6 (SEM 2·8)) availability. Legumes are low-GI foods (, 55), ranging from 6 (chickpeas) to 13 (mung beans). Kidney beans showed significant reductions for both total (6 %) and LDL-cholesterol (9 %), and groundnuts for total cholesterol (7 %; P,0·05). We conclude that mineral availability from legumes differs and may be attributed to their mineral content, mineral -mineral interaction and from their phytic and tannic acid content; legumes are considered low-GI foods and have shown potential hypocholesterolaemic effects. The above studies can be a scientific basis for considering legumes as functional foods.

No abstract

Brown rice is a good source of dietary fibre (DF) and contains higher vitamins/minerals than milled rice. The study determined the effect of amylose content (AC) and DF on glucose response (GR) from different varieties of milled and brown rice. Milled and brown rice were used as test foods. They were fed to 9-10 human volunteers containing 50 g available carbohydrate after an overnight fast. GR and the glycemic index (GI) were determined. Results found that Sinandomeng with the lowest AC had a high GI = 75, while PSBRc10 with the highest AC had a low GI = 50. Sinandomeng with a low DF had GI = 75, while its brown rice had GI = 55. Brown rice (IR64) with 23% AC and DF of 2.5 g/100 g had low GI = 51. In conclusion, the GR and GI of the different varieties of cooked milled and brown rice varied depending on its AC and DF contents.

Summary Reliably generating rice varieties with low glycaemic index ( GI ) is an important nutritional intervention given the high rates of Type II diabetes incidences in Asia where rice is staple diet. We integrated a genome‐wide association study ( GWAS ) with a transcriptome‐wide association study ( TWAS ) to determine the genetic basis of the GI in rice. GWAS utilized 305 re‐sequenced diverse indica panel comprising ~2.4 million single nucleotide polymorphisms ( SNP s) enriched in genic regions. A novel association signal was detected at a synonymous SNP in exon 2 of LOC _Os05g03600 for intermediate‐to‐high GI phenotypic variation. Another major hotspot region was predicted for contributing intermediate‐to‐high GI variation, involves 26 genes on chromosome 6 ( GI 6.1). These set of genes included GBSSI , two hydrolase genes, genes involved in signalling and chromatin modification. The TWAS and methylome sequencing data revealed cis ‐acting functionally relevant genetic variants with differential methylation patterns in the hot spot GI 6.1 region, narrowing the target to 13 genes. Conversely, the promoter region of GBSSI and its alternative splicing allele (G allele of Wx a ) explained the intermediate‐to‐high GI variation. A SNP (C˃T) at exon‐10 was also highlighted in the preceding analyses to influence final viscosity ( FV ) , which is independent of amylose content/ GI . The low GI line with GC haplotype confirmed soft texture, while other two low GI lines with GT haplotype were characterized as hard and cohesive. The low GI lines were further confirmed through clinical in vivo studies. Gene regulatory network analysis highlighted the role of the non‐starch polysaccharide pathway in lowering GI .

The dietary fibre and fermentability characteristics of local root crops and legumes were determined. Total, soluble and insoluble fibre were determined in six root crops (kamote, gabi, potato, tugi, ube, cassava) and ten legumes (mungbean, soyabean, peanut, pole sitao, cowpea, chickpea, green pea, lima bean, kidney bean and pigeon pea) using Association of Official Analytical Chemists methods. The dietary fibre from test foods was isolated and fermented in vitro using human faecal inoculum simulating conditions in the human colon. The SCFA, e.g. acetate, propionate, butyrate, produced after fibre fermentation was measured using HPLC. The dietary fibre content of root crops ranged from 4·6 to 13·5 g/100 g while legumes ranged from 20·9 to 46·9 g/100 g, suggesting that root crops and legumes are good sources of dietary fibre. Significant amounts of SCFA were produced after in vitro fermentation of the fibre isolate of both root crops and legumes. The best sources (as mmol/g fibre isolate) of acetate among the legumes were pole sitao (5·6 (SEM 0·5)) and mungbean (5·3 (SEM 0·1)) and among the root crops, tugi (2·5 (SEM 0·4)) and cassava (2·4 (SEM 0·1)); of propionate, kidney bean (7·2 (SEM 1·5)) and pigeon pea (3·3 (SEM 0·2)) for legumes, and tugi (1·8 (SEM 0·2)) for root crops; and of butyrate, peanut (6·0 (SEM 0·2)) and cowpea (5·4 (SEM 0·2)) for legumes, and tugi (0·8 (SEM 0·0)) and cassava (0·8 (SEM 0·0)) for root crops. In conclusion, root crops and legumes are good sources of dietary fibre and produced SCFA after fibre fermentation, such as acetate, propionate and butyrate. SCFA production after in vitro fermentation can be estimated using human faecal inoculum and can be used to model the human colon.