DEGRADATION KINETICS OF FOOD MACROMOLECULES DURING SORGHUM GERMINATION (original) (raw)
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International Journal of Food Science and Biotechnology, 2018
The effect of germination time, during malting, on phytate and tannin concentration as well as on the in-vitro protein digestibility of some sorghum types was investigated. The increase in the germination time led to a decrease in the phytate content from the initial range of 1004.6-1097.4 mg/100g, at zero-hour germination, to a range of 457.2-626.3 mg/100g at 48-hour germination time. A further decrease in the phytate content was obtained at 96-hour germination time with a range of 215.4-298.3 mg/100g. A maximum of 71.5-79.2% phytate reduction capacity at 96-hour germination time was attainable with the sorghum types. The increase in germination time also caused the tannin concentration to decrease. The initial tannin concentration (0.23-4.47 mg/g), at zero-hour germination time, decreased to 0.15-3.35 mg/g at 48-hour germination time while a range of 0.13-3.07 mg/g was obtained at 96-hour germination time. A maximum of 25.9-45.8% tannin reduction capacity at 96-hour germination time was attainable with the sorghum types. The in-vitro protein digestibility of the sorghum types increased from the initial level (32.1-45.1%), at zero-hour germination time, to 42.8-61.3% at 48-hour germination time while that of 96-hour germination time was 46.7-64.8%. It may be concluded that the decrease in the anti-nutritional factors and improvement in the protein digestibility of sorghum types during the malting process was essentially a function of germination time and sorghum grain variability.
Influence of the Fermentative Flora on the Carbohydrate content of Sorghum Grains
Microbial fermentation activates many endogenous enzymes that help improve the nutritional value of cereals. The present study aimed to determine the effect of the fermentation flora on the carbohydrate content of hulled and non-hulled sorghum grains fermented for 72 hours. The fermentation process, the enumeration of the total mesophilic aerobic flora, yeasts and molds and the total carbohydrate contents were made according to standard analysis methods. The pH of the fermentation waters was recorded every 24 hours. The results showed a significant drop in pH over fermentation time from 6.05 to 4.14 for hulled sorghum grains fermented for 72 hours. The evolution of loads in total mesophilic aerobic flora and yeasts and molds resulting in the drop in pH in unhulled sorghum grains is linked to alcoholic fermentation and that in hulled grains to lactic and acetic fermentation. The production of metabolites responsible for the drop in pH during fermentation would be linked to the degradation of carbohydrate compounds. Spontaneous fermentation of sorghum grains allowed the degradation of carbohydrate molecules and this could also be accompanied by an improvement in the bioavailability of nutrients contained in the grains.
Protein Solubility, Digestibility and Fractionation after Germination of Sorghum Varieties
The changes in crude protein, free amino acids, amino acid composition, protein solubility, protein fractionation and protein digestibility after germination of sorghum were investigated. Sorghum varieties (Dorado, Shandaweel-6, Giza-15) were soaked for 20 h followed by germination for 72 h; the results revealed that crude protein and free amino acids in raw sorghum varieties ranged from 10.62 to 12.46% and 0.66 to 1.03 mg/g, respectively. Shandaweel-6 was the highest variety in crude protein and free amino acids content. After germination, crude protein was decreased and free amino acids were increased. There was an increase in content of valine and phenylalanine amino acids after germination. On the other hand, there was a decrease in most of amino acids after germination. After germination protein solubility was significantly increased. Regarding protein fractions, there was an increase in albumin, globulin and kafirin proteins and a decrease in cross linked kafirin and cross linked glutelin after germination.
Fermentability and degradability of sorghum grain following soaking, aerobic or anaerobic treatment
Animal Feed Science and Technology, 2005
This study determined the effect of soaking (steeping), aerobic (germination) and anaerobic (reconstitution) treatments on the solubility of carbohydrate and nitrogen, and on the in vitro fermentability and in sacco degradability of dry matter (DM) of sorghum grain (Sorghum bicolor cv Western Red). Samples of grain were dry rolled (DR, control), soaked (SK), stored anaerobically for 21 d (reconstitution, AS21), stored aerobically for 5 d (germination, G5) or stored aerobically for 5 d and then anaerobically for 16 d (G5AS16). Compared to the DR treatment, only G5AS16 treatment reduced (P < 0.05) starch content by 2% units. Free sugar and buffer-soluble nitrogen contents were higher (P < 0.05) in G5 and G5AS16 sorghum (21 and 54 g kg −1 DM; 241 and 375 g kg −1 total nitrogen, respectively) than in DR sorghum (8 g kg −1 DM; 142 g kg −1 total nitrogen, respectively). Free sugar and buffer-soluble nitrogen contents were similar (P > 0.05) for SK, AS21 and DR control sorghum. Following a 5-h incubation in buffered rumen liquor, G5 and G5AS21 treatments increased (P < 0.05) the in vitro fermentability of sorghum compared to the DR control treatment. This was indicated by increases in gas production (121-215%), volatile fatty acid (VFA) production (98.6-210%) and the amount of starch fermented (22-47%), following a 5-h incubation with buffered rumen liquor. In sacco degradability of DM in sorghum after 48 h of incubation was higher for G5 and G5AS16
Ethiopian Journal of Science and Technology
The effect of germination duration on proximate, minerals, anti-nutritional factors and functional properties of two local sorghum varieties (Girana and Miskr) were investigated. A 2*3*2 full factorial design was used to conduct the experiment. Sorghum varieties were soaked for 24 hours at room temperature and germinated for 24, 48 and 72 hours in duplicate. The germinated and control sorghum grains were milled. The analysis and measurement of dependent variables were done in triplicate. The collected data were subjected to analysis of variance using SPSS statistical software. On average after 72 hours germination 9.68% and 9.52% reduction in pH and 34.5% & 16.6% increase in TTA was observed which may improve product stability and mineral absorption. Similarly crude protein content showed a significant (p<0.05) increase from 10.35±0.04% to 12.59±0.15% and 10.17± 0.02 to 12.75±0.136% for Girana and Misker varieties, respectively. A significant (p< 0.05) decrease in crude fat and carbohydrate content was observed for both varieties that in turn brought about a decrease in the average energy value of nearly 8kcal/100gm of sorghum flour. Germination resulted in a significant (p< 0.05) average 50% and 53 % reduction in phytate and tannin content of Girana and Misker varieties respectively. Germination shows a significant (p < 0.05) increase of iron from 7.15±0.03 to 7.51±0.23 and from 7.42±0.1 to 7.85±0.17 at 48 hours for Girana and Misker varieties respectively. Moreover, phytate/zinc molar ratio significantly decreased well below 15 for both varieties. Improvement in functional properties of sorghum as measured by WAI, WSI and viscosity was also observed after 72 hours germination.
Pakistan Journal of Nutrition, 2008
Two sorghum cultivars namely, Mugud (low tannin) and Karamaka (high tannin) were used in this study. The flour of the seeds of both cultivars was mixed with 5% malt. Then the flour with or without malt was fermented for 16 h. Samples were taken every 2 h during fermentation to study changes in pH, total acidity, crude protein and dry matter. Fermentation of the flour with or without malt resulted in an increase in crude protein content and total acidity for both cultivars. Moreover, the fermented flour with or without malt was cooked to study changes in phytate, tannins and in vitro protein digestibility of the cultivars. A highly significant (P < 0.05) reduction in antinutritional factors (phytate and tannins) was observed for malted and fermented flour compared to the fermented dough. Cooking significantly (P < 0.05) reduced the in vitro protein digestibility of the treated cultivars but the extent of the reduction is lower in malted samples. Fermentation alleviates the adverse effect of cooking on sorghum protein digestibility after addition of malt. Results obtained revealed that addition of malt followed by fermentation is a useful method to improve the nutritional value of sorghum even after cooking.
Journal of Food Science and Technology, 2019
Germination can be used as a bio-processing practice to enhance the digestibility of nutrient and improve the bioactive compounds and rheological properties of food grains. In the present study, effect of germination time 12, 24, 36 and 48 h and temperature 25, 30 and 35°C on carbohydrate profile, enzyme activity, in vitro nutrient digestibility, antioxidant activity, bioactive components and rheological characteristics of sorghum was examined. As time and temperature for germination progressed, it considerably enhance the activity of diastase enzyme and also the sugar content by hydrolysis of starch and further enhance the in vitro digestibility of starch by 10.50-36.25%. Germinated sorghum had high in vitro protein digestibility and it ranges from 57.50 to 77.91% as compared to native sorghum (54.09%). Germination of sorghum for longer time period at elevated conditions appreciably improve the antioxidant activity by 4.24-52.96%, total phenolic content and flavonoid content by 1.60-4.09 mgGAE/g and 60.30-94.03 mgQE/100 g, respectively Similarly reducing power increased from 29.27 to 47.19 lg AAE/g and metal chelating activity enhanced 19.48-52.09% as period for germination goes from 12 to 48 h and temperature from 25 to 35°C. Increased enzyme activity during germination degrades the starch and thus lowers down the peak and final viscosity of sorghum. Increased enzymatic activity and higher antioxidant activity also lower down the lightness value by 12.48% while a* was increased by 6.78%. Germination of sorghum thus offers a tool to increase the nutrient digestibility and bioactive potential of sorghum without any chemical or genetic engineering.
Physical and chemical properties associated with food quality in sorghum
South African Journal of Plant and Soil, 2005
Samples of 13 genetically diverse sorghum [Sorghum bicolor (L.) Moench] accessions were analysed for physical properties and chemical composition. The food (injera) quality and the phenolic (condensed tannins) content of six sorghum samples were also determined. The accessions showed a wide variation in protein (7.99 to 17.8%), lipids (2.52 to 4.76%), starch (51.88 to 85%), and amylose (12.30 to 28.38%) content. Grain weight varied in a wide range, and endosperm texture varied from intermediate to completely starchy. Linoleic acid (18:2) and oleic acid (18:1) were the major fatty acid constituents of sorghum lipids. Only a few significant correlations were observed among the physical and chemical properties. Three of the six accessions used for sensory analysis, namely Ambajeettee, AL-70 and ETS 2752 were chosen for their desirable properties in injera making. The chemical and physical properties of the selected accessions were characterised by high protein content, low tannins, intermediate endosperm texture, and white seed colours. Red seeded sorghum and white seeded sorghum with pigmented testa were found to be less desired.
2011
Total energy, protein content and digestibility, antinutritional factors, and total and extractable minerals of normal sorghum (Type II) and four newly developed lines of sorghum (Eri-1, SHK-ABA-4, SHK-ABA-6 and SHK-ABA-10.) were studied before and after fermentation. Phytic acid and Tanin contents of raw flour of the normal sorghum were, respectively, 41.73 mg 100 g-1 and 170.54 mg 100 g-1 , while the same values for the four lines ranged from 16.07 to 38.64 mg 100 g-1 and from 31.90 to 184.25 mg 100 g-1 , respectively. Polyphenols content of raw flour of the normal sorghum was 604.56 mg 100 g-1 , exceeding the values found for the four lines in the range of 476.46 to 544.44 mg 100 g-1. According to our results, fermentation of normal sorghum flour and that of the new lines significantly (P≤ 0.05) decreased the antinutritional factors i.e. phytate, tannins, and polyphenols. The total energy of raw flour of the normal sorghum was 369.87 Kcal 100 g-1 while it ranged from 367.23 to 372.57 Kcal 100 g-1 for the new lines. In all cases, this energy slightly decreased after fermentation. Protein digestibility of normal sorghum was 22.60% and, for the new lines, it ranged from 37.00 to 57.19%. After fermentation, protein digestibility and the total and extractable Ca, P, and Fe increased significantly (P≤ 0.05) for all genotypes studied.
BIO web of conferences, 2022
Sorghum is a local commodity that has the potential as an alternative ingredient to replace the use of wheat flour in food products. Food security can be accomplished by replacing wheat with sorghum, which is supported by sustainable agriculture. Germination is one of the economical and environmentally friendly modification techniques, it affects the physicochemical properties of seed flour as well as increase the lightness, water and oil holding capacity (WHC/OHC), swelling, and solubility. The goal of the study is to ascertain how germination affects the physicochemical characteristics of sorghum flour and to use principal component analysis (PCA) and hierarchical clustering analysis (HCA) to assess the link between each parameter and its cluster. The germination had an impact on the moisture content, ash, redness (a*), yellowness (b*), viscosity, final viscosity, holding strength, breakdown, and setback of germinated sorghum, but it also increased lightness (L*) and solubility. In white sorghum germination, WHC, OHC, and swelling capacity were increased; but these did not significantly different in red sorghum germination. The protein, fat, breakdown, redness value (a*), peak viscosity, pasting temperature, and peak time were all positively connected, according to PCA, while OHC and lightness (L*) were negatively correlated.