Effect of germination and pure culture fermentation on HCl-extractability of minerals of pearl millet (Pennisetum typhoideum)

Germination significantly increased inorganic P, non-phytate P and phosphorus extractable in 0.03 N HCl, the concentration of acid found in human stomach, with a corresponding decline in phytate P of pearl millet grains. HCl-extractability of calcium, iron, zinc, copper and manganese, an index of their bioavailability to humans, was also significantly improved by germination. Fermentation of pearl millet sprouts with mixtures of yeasts ( Saccharomyces diastaticus or Saccharomyces cerevisiae ) and lactobacilli ( Lactobacillus brevis or Lactobacillus fermentum ) generally improved extractability of the minerals of the sprouts, probably because of the decreased content of phytic acid in the germinated and fermented pearl millet sprouts.     

Phytic acid and extractable phosphorus of pearl millet flour as affected by natural lactic acid fermentation

Lactic acid fermentation of pearl millet flour decreased its phytic acid content and increased extractable phosphorus. Fermentation at 40 and 50°C for 72 h or longer eliminated phytic acid almost completely; extractable phosphorus was more than doubled. Lower temperatures (20 and 30°C) were less effective. The changes in concentration of phytic acid and extractable phosphorus may be attributed partly to phytase activity inherent in pearl millet flour.     

Nutritional evaluation of high protein genotypes of pearl millet (Pennisetum americanum (L.) leeke)

Three high protein (HP) inbred lines (700112, WC-190 and B-816) of pearl millet were studied for their nutritional quality and the results compared with those of normal protein varieties. The protein content of HP lines showed an average increase of 60% but the starch and soluble sugars together and the fat content decreased by 40 and 20%, respectively. Total dietary fibre of the HP lines was about 10% higher. A decrease (about 20%) in the albumin fraction was associated with an increase in prolamin in HP lines. The amino acid composition of the HP lines remained normal except for an approximately 16% decrease in lysine. However, the total amount of lysine in the sample increased by an average of 37%, as a result of a substantial increase in protein content. True protein digestibility was very high for each line but, expectedly, the biological value was markedly lower. The values for utilisable protein were highest for high protein genotypes. Digestible energy was high in all the genotypes, although slightly lower values were obtained for the HP lines; this was attributed to the fibre fractions.     

Comparative study of phytic acid content,in-vitro protein digestibility and amino acid composition of different types of flat breads

Phytic acid content of eight different types of leavened and unleavened flat breads was determined. It was highest in unleavened and non-fermented whole wheat chapati and lowest in the leavened and fermented white wheat flat bread roghni nan. The effect of baking conditions, bread composition and phytic acid content on in-vitro digestibility of protein was measured using a pepsin multienzyme pH stat technique. The amino acids released were separated by ultrafiltration. The rate of protein digestibility of flat bread and amino acid released depended upon the type of flour used, baking conditions, phytic acid content and other antiproteolytic constituents of breads. Leavening and fermentation of breads resulted in an increase of protein digestibility and availability of amino acids. Addition of soya flour increases the protein digestibility of breads whereas millet flour decreases it.     

Physicochemical,rheological, morphological,and in vitro digestibility properties of cross-linked starch from pearl millet cultivars

The effect of epichlorohydrin (0.5%) as a cross-linking agent on physicochemical, rheological, morphological, and in vitro digestion properties of pearl millet starches from different cultivars was studied. Degree of cross-linking (DC) ranged between 40.61% and 89.75%, lower values of DC were observed for cv.HC-10 and cv.HHB-67 whereas higher values were observed for cv.HHB-223 and cv.GHB-732. Cross-linked starch from cv.GHB-732 showed the lowest amylose content, swelling power, and solubility as compared to other cultivars. Rheological properties of starches during heating showed their elastic behaviour. G′ value was much higher than the G′′ value at all frequency values for starch pastes. Plots of shear stress (σ) versus shear rate (γ?) data for cross-linked starch pastes were fitted to Herschel-Bulkley model and yield stress (σ_o), flow behaviour index (n), and consistency index (K) were evaluated. Scanning electron micrographs (SEM) investigations revealed that cross-linked starch granules had slightly rough surfaceand grooves with slight fragmentations. Readily digestible starch (RDS) of cross-linked starches varied from 46.1% to 50.6%, cv.GHB-732 had the lowest value. Slowly digestible starch (SDS) and resistant starch (RS) content of cross-linked starches ranged from 34.5% to 36.4% and 13.6% to 19.4%, respectively. cv.HC-10 had the highest value for SDS content while the highest RS content was observed for cv.GHB-732. In comparison to native starches, cross-linked modification decreased SDS and RDS content whereas RS content was increased.     

Influence of storage on the protein quality of pearl millet flour

Whole grain flours of two cultivars of pearl millet (Pennisetum typhoides Rich) were stored in cans for 8 days at the prevailing room temperature (25±5°C), until the flours developed an off-flavour and bad taste. The flour samples were then evaluated for protein quality. The values of protein efficiency ratio, true digestibility, biological value, net protein retention and protein utilisation fell markedly during storage. The protein quality of the cultivar with the higher amount of oil was affected more severely.     

Effect of fermentation on in vitro digestibilities and the level of antinutrients in moth bean [Vigna aconitifolia (Jacq.) Marechal]

The effect of fermentation with varying temperatures and time periods on the nutritive value of Moth bean was studied. Results indicated that at 30 °C, protein digestibility increased from 60% in the non‐processed moth bean to 77%, 78% and 80% and at 35 °C, increased to 81%, 83% and 85% following 12, 18 and 24 h of fermentation (controlled) period, respectively. Fermentation also caused an appreciable enhancement (96–133%) in starch digestibility with increase in period and temperature of fermentation. Fermentation of moth bean resulted in 24–34% reduction in phytic acid content at 30 °C and 33–42.5% at 35 °C. Polyphenol content was reduced by 42%, 48% and 51% at 30 °C and by 44%, 49% and 54% at 35 °C after 12, 18 and 24 h of fermentation period, respectively. Prolonging the period of fermentation from 12 to 18 and 24 h at 30 °C also caused a loss in TIA.     

Effect of water deficit on yield and protein content in pearl millet grains

Seventy-two pearl millet genotypes were water stressed at panicle development and grain filling stages. Neither grain yields, yield components, protein percent nor total protein per unit area were affected by water deficit during panicle development but protein content per grain was increased. When plants were water stressed during grain filling, grain yield, grains per unit area and 1000 grain weight were reduced, but grain protein percentage increased. Total protein per unit area was reduced primarily due to lower grain yield. The protein content per grain was unaffected by stress, suggesting that the apparent increase in protein percentage is due to reduced carbohydrate accumulation under stress.     

Influence of depigmentation of pearl millet (Pennisetum gluacum L.) on sensory attributes, nutrient composition and in vitro digestibility of biscuits

Presence of high concentration of pigments in the pericarp and endosperm regions of pearl millet imparts undesirable gray color to its products. This study attempts to improve the acceptability of pearl millet products through processing technique and to study its effect on nutritional composition of pearl millet product. Pearl millet grains were depigmented by soaking in 0.2 N HCl for 18 h followed by washing, blanching at 98°C for 30 s and sun drying. Three different types of biscuits were prepared from refined flour (Reference), native or unprocessed pearl millet (T-I) and depigmented pearl millet (T-II). Results indicated that depigmentation improved the sensory attributes especially the color of pearl millet biscuits (T-II). The protein, fat, ash and total dietary fiber of pearl millet based biscuits (T-I as well as T-II) were significantly (P?0.05) higher than the reference biscuits. Depigmentation significantly improved the in vitro starch digestibility, in vitro protein digestibility and the soluble dietary fiber content of pearl millet biscuits (T-II) by 14.50, 6.56 and 6.18%, respectively. On the other hand, a significant decrease of 6.73, 2.43 and 17.03 g/100 g in protein, starch and insoluble dietary fiber was detected in pearl millet biscuits (T-II) due to depigmentation.     

Supplementation of pearl millet flour with soybean protein: effect of cooking on in vitro protein digestibility and essential amino acids composition

In vitro protein digestibility (IVPD) and amino acids profile of pearl millet (Dempy cultivar) supplemented with soybean protein (5–15%) were investigated. Supplementation of dempy flour with soybean protein steadily decreased IVPD with increasing the portion of soybean in the blend. The in vitro protein digestibilities of the cooked supplemented dempy flours were higher when compared with the raw ones, whereas the highest value was that of the 5% soybean protein. All essential amino acids of dempy flour were enriched on supplementation with soybean protein. The levels of amino acids increased with increasing the amount of soybean protein in the blend. Essential amino acids in dempy supplemented with 15% soybean are comparable to those in the FAO reference pattern. Supplementation increased significantly lysine to 1.5–2.4 folds. Essential amino acids content remained higher in the cooked composite flours when compared with the cooked native dempy flour.     

Effect of processing on starch fractions in different varieties of finger millet

The effect of processing on starch fractions in finger millet (ragi) was studied in a standardized system and convenience mixes. In raw varieties, rapidly available starch (RDS) was 8.3% to 11.1% with slowly digestible starch (SDS) of 26.4% to 35.3%, and total available starch (TAS) 39–53%. The changes in the SDS and TAS were statistically significant. Puffing resulted in an increased RDS and decreased SDS. The changes were more prominent in hill grown varieties as compared to base varieties. Resistant starch (RS) ranged from 0.9% to 1.0% among raw varieties and decreased during puffing. The effect of puffing on gelatinisation of ragi flour was investigated, MR-1 variety showed a single phase transition with gelatinisation temperature of 64 °C, the same was found to be absent in puffed flour reflecting the gelatinisation during puffing. RS formation was influenced by the processing methods, increased during pressure cooking and roasting while dietary fiber increased during cooking and both decreased in all other processing methods. However, its implication in the convenience mix has shown that other ingredients also play a role in the RS content.     

Effect of fermentation on biochemical and sensory characteristics of millet flour supplemented with whey protein

Pearl millet like other cereals shows qualitative and quantitative deficiency in protein. The main objective of this study was to obtain the food of high nutritive value with high protein content and biological value by supplementing pearl millet, with whey protein. Two levels of whey protein were considered (20% and 25% protein content). Supplemented samples and control were fermented in the presence of starter for 14 h according to the traditional method utilised in Sudan. The pH, crude protein, in vitro protein digestibility (IVPD) and protein fractions of the fermented and supplemented pearl millet were determined at 2‐ h intervals. Supplementation of whey protein resulted in significant increase in protein content compared to the control, i.e. 14.8%, 23.9% and 28.7% for Ashana control (AC), Ashana plus whey protein (20% protein content) (AW₁) and Ashana plus whey protein (25% protein content) (AW₂), respectively. Fermentation was found to cause a highly significant (P ≤ 0.05) improvement in IVPD for AC, AW₁ and AW_2. The major protein fraction in the whey protein supplemented doughs was the globulin. This would indicate an improvement in the nutritional quality of pearl millet. Sensory evaluation revealed higher acceptability for whey protein supplemented formulas compared to control.     

Effect of various types of fermentation on in vitro protein and starch digestibility of differently processed pearl millet

Pearl millet (Pennisetum typhoideum) grains were fermented with Lactobacilli and yeast alone, in combination and with natural flora at 30 °C for 48 h after giving various processing treatments viz, fine and coarse grinding, soaking, debranning, dry heat treatment, germination and autoclaving after adding of water. Fermentation was carried out with Lactobacillus acidophilus and Rhodotorula isolated from naturally fermented pearl millet and Lactobacillus acidophilus, Candida utilis and natural fermentation using freshly ground pearl millet flour as inoculum. All the processing treatments except coarse grinding improved the protein and starch digestibility. Autoclaving enhanced the digestibilities of processed samples which was further improved by different types of fermentation, the maximum being in case of germinated and naturally fermented pearl millet. A combination of Lactobacilli and yeast was more effective in increasing the protein as well as starch digestibility as compared to pure culture fermentation.     

In vitro protein and starch digestibility of pearl millet (Pennisetum gluacum L.) as affected by processing techniques

The effect of malting and blanching on the in vitro protein and starch digestibility of pearl millet (Pennisetum gluacum L.) were investigated. Pearl millet seeds were subjected to malting [steeping (16 h), germination (48 and 72 h) and kilning (24 h at 50 degrees C)] and blanching (30 s at 98 degrees C) treatments, before grinding to flour. The results indicated that both the treatments improved the in vitro digestibility significantly. Malting appreciably improved the in vitro protein (14-26%) and starch (86-112%) digestibility and improvement by malting was significantly higher than blanching. The effect of malting with 72 h of germination was most remarkable in improving the in vitro protein and starch digestibility.     

Effect of urea and by-products on the in-vitro fermentation of untreated and urea treated finger millet (Eleusine coracana) straw

The in-vitro fermentation characteristics of untreated and 50 g litre^?1 urea-treated finger millet (Eleusine coracana) straw with four supplements (urea, rice bran, cottonseed and groundnut cakes) at three different ratios of straw: supplement were investigated. Gas production was greater from treated than untreated straw; groundnut cake was the most rapidly fermented supplement followed by cottonseed cake and rice bran. Urea incubated alone inhibited gas production. Untreated and treated straws were incubated with 22, 30 and 37 g rumen degradable nitrogen from the supplements per kg organic matter digested. Significant (P < 0.05) positive interactive effects on gas production were observed with untreated straw at all three levels of groundnut cake supplementation after 12, 52 and 166 h incubation. Similar interactions were observed for cottonseed cake supplementation of untreated straw and groundnut cake supplementation of treated straw, although statistical significance was not achieved for all supplementation levels at the three times for which data were analysed. No consistent significant interactive effects in gas production were observed between cottonseed cake and treated straw. Rice bran inhibited gas production after 12 h but, subsequently, had little effect on either type of straw. Urea inhibited the gas production from both straws at all three ratios of supplementation. Urea also significantly reduced dry matter disappearance of treated straw at two of three levels of urea supplementation. Interactive effects on gas production were most pronounced in the early stages fermentation and appeared to be related to the high content of highly fermentable material particularly in groundnut cake but also in cottonseed cake.     

Selection of barley grain affects ruminal fermentation, starch digestibility, and productivity of lactating dairy cows

The objective of this study was to evaluate the effects of 2 lots of barley grain cultivars differing in expected ruminal starch degradation on dry matter (DM) intake, ruminal fermentation, ruminal and total tract digestibility, and milk production of dairy cows when provided at 2 concentrations in the diet. Four primiparous ruminally cannulated (123 ± 69 d in milk; mean ± SD) and 4 multiparous ruminally and duodenally cannulated (46 ± 14 d in milk) cows were used in a 4 × 4 Latin Square design with a 2 × 2 factorial arrangement of treatments with 16-d periods. Primiparous and multiparous cows were assigned to different squares. Treatments were 2 dietary starch concentrations (30 vs. 23% of dietary DM) and 2 lots of barley grain cultivars (Xena vs. Dillon) differing in expected ruminal starch degradation. Xena had higher starch concentration (58.7 vs. 50.0%) and greater in vitro 6-h starch digestibility (78.0 vs. 73.5%) compared with Dillon. All experimental diets were formulated to supply 18.3% crude protein and 20.0% forage neutral detergent fiber. Dry matter intake and milk yield were not affected by treatment. Milk fat concentration (3.55 vs. 3.29%) was greater for cows fed Dillon compared with Xena, but was not affected by dietary starch concentration. Ruminal starch digestion was greater for cows fed high-starch diets compared with those fed low-starch diets (4.55 vs. 2.49 kg/d), and tended to be greater for cows fed Xena compared with those fed Dillon (3.85 vs. 3.19 kg/d). Ruminal acetate concentration was lower, and propionate concentration was greater, for cows fed Xena or high-starch diets compared with cows fed Dillon or low-starch diets, respectively. Furthermore, cows fed Xena or high-starch diets had longer duration that ruminal pH was below 5.8 (6.6 vs. 4.0 and 6.4 vs. 4.2 h/d) and greater total tract starch digestibility (94.3 vs. 93.0 and 94.3 vs. 93.0%) compared with cows fed Dillon or low-starch diets, respectively. These results demonstrate that selection of barley grain can affect milk fat production and rumen fermentation to an extent at least as great as changes in dietary starch concentration.     

Starch hydroxyalkylation: Physicochemical properties and enzymatic digestibility of native and hydroxypropylated finger millet (Eleusine coracana) starch

Starch was isolated from finger millet (Eleusine coracana) and it was etherified with propylene oxide to produce hydroxypropylated derivative. The specific specie used in this study is African finger millet known as jeero. The yield of starch obtained from finger millet on dry weight basis was 52.4%. Progressive increases in molar substitution (MS) were observed as the volume of propylene oxide added to the reaction medium increased. The X-ray pattern of native finger millet starch conforms to the ‘A’ diffraction pattern characteristics of cereal starches. Prominent peaks were observed at around 2θ=15°, 17°, 18° and 23° and weaker peaks at around 2θ=20° and 26°. No pronounced differences were observed between the diffractograms of native starch and the hydroxypropyl derivatives. Hydroxypropylation improved the free swelling capacities of the native starch at all temperatures studied (30–90 °C). Turbidity of unmodified finger millet starch paste increased progressively as the days of storage increased. Turbidity reduced remarkably after hydroxypropylation and reduction in turbidity was observed as the MS of the modified starches increased. Hydroxypropylation reduced pasting temperature, increased peak viscosity but reduced setback value. In addition, hydroxypropylation reduced percentage syneresis of the unmodified starch. Retrogradation properties monitored with differential scanning calorimetry reveals that starch retrogradation reduced reasonably after hydroxypropylation. Carbon 13 NMR spectroscopy reveals that hydroxypropylation took place predominantly on carbon 6 on the anhydroglucose unit (AGU).     

Short-chain fatty acid content and pH in caecum of rats fed various sources of starch

Caecal pH and contents of short-chain fatty acids (SCFA) were registered in rats fed three potential sources of resistant starch (RS); raw pea starch, raw potato starch, and an RS-enriched preparation obtained from wheat starch by autoclaving and enzymatic incubation. Small intestinal digestibility and delivery of RS to the hind-gut in the case of raw starches were determined by analysis of faecal starch in animals treated with antibiotics to prevent hind-gut fermentation. RS content in the RS-enriched preparation was determined as total starch remaining in an enzymatic gravimetric dietary fibre residue. The fermentability of RS was estimated from the faecal recovery of starch in normal animals with intact hind-gut microflora. Approximately 35 g per 100 g and 32 g per 100 g were RS in the case of raw potato starch and the RS-enriched preparation, respectively, versus only 1 g per 100 g in the case of raw pea starch. The caecal pH decreased with all test diets, being most significant with raw potato starch. SCFA production and faecal bulking were negligible with raw pea starch, whereas both raw potato starch and the RS-enriched preparation significantly increased these parameters. The fermentability of RS in raw potato starch and the RS-enriched preparation was similar, or about 60–70%. If calculated on basis of fermented amount, RS in raw potato starch was more potent in generating SCFA (49 μmol g^?1) than in the RS-enriched preparation (19 μmol g^?1). RS in raw potato starch also displayed the highest faecal bulking capacity. In fact, the faecal dry weight increased more than expected merely from delivery of RS. The relative proportion in caecal contents of acetic-, propionic- and butyric acid was 70, 17 and 8%, respectively, with no significant differences between the three sources of RS.     

Indigenous legume fermentation: Effect on some antinutrients and in-vitro digestibility of starch and protein

Indigenous fermentation of coarsely ground dehulled black-gram dhal slurry at 25, 30, and 35°C for 12 and 18 h reduced the levels of phytic acid and polyphenols significantly (P < 0·05). The unfermented legume batter had high amounts of phytic acid (1000 mg/100 g) and polyphenols (998 mg/100 g), and these were reduced to almost half in the product fermented at 35°C for 18 h. In-vitro digestibility of starch and protein improved significantly (P < 0·05) with increase in the temperature and period of fermentation. A significant (P < 0·01) and negative correlation found between the in-vitro digestibility and the anti-nutrient further strengthens these findings.