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Lorraine L. Niba |
Total Records (
2 ) for
Lorraine L. Niba |
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Lorraine L. Niba
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Nick Rose
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Legume starches are typically more resistant to digestion than various other starches, rendering them low glycemic index foods, and potential substrates for beneficial colonic fermentation. The presence of oligosaccharides however reduces acceptability of various legumes. This study aimed to quantify resistant starch levels in some commonly consumed legumes - adzuki, fava, lima and mung bean - and assess the effect of varying soaking solution concentration on resistant starch and oligosaccharides. Legume samples were treated for twelve hours with either 1 % or 5 % citric acid or sodium bicarbonate solutions. A control sample was soaked in distilled water. These were autoclaved at 120 oC and freeze dried. Samples were analyzed for resistant starch by the procedure of McCleary and Monaghan 2002, and for oligosaccharides using a Megazyme? analysis kit. Adzuki bean had the lowest resistant starch content in the distilled water controls (2.94 g /100 g dry weight), while fava bean had the highest resistant starch content (5.15 g /100 g dry weight). Treatment with 5 % bicarbonate solution, decreased resistant starch in all legumes, while soaking in 5 % citric acid solution resulted in increases in resistant starch. Soaking in 5 % citric acid or sodium bicarbonate resulted in decrease in total starch, except for lima bean. There were minimal changes in oligosaccharide levels. Concentration of pre-process soaking solution therefore has considerable effect on resistant starch formation and retention, and a less noticeable effect on oligosaccharide levels. |
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Lorraine L. Niba
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Resistant starch, beta-glucan and fructo-oligosaccharide are physiologically beneficial carbohydrates which have been associated with the prevention and management of some diet-related diseases. Various plants are therefore being examined as potential sources of non-digestible oligosaccharides. The objective of this study was to quantify these carbohydrates in unripe plantain and to assess the effect of moist heat processes such as autoclaving and parboiling. Unripe plantain was chipped and either parboiled (60 0C or 100 0C) or autoclaved (120 0C or 130 0C) and freeze-dried for 72 hours. Sample material was processed and assayed in duplicate for glucose, fructose, lactose, fructo-oligosaccharide, -glucan and resistant starch content. Glucose content ranged from 0.90 g/100 g to 1.62 g/100 g. Sucrose content ranged from 1.48 g/100 g to 3.87 g/100 g. Lactose content ranged from 0.49 g/100 g to 3.82 g/100 g. Fructo-oligosaccharide levels decreased from 0.67 g/100 g to 0.59 g/100 g with processing, while -glucan content was unchanged. Resistant starch content decreased from 53.6 g/100 g in unprocessed plantain to 3.69 g/100 g in samples autoclaved at 120 oC. While fructo-oligosaccharide and -glucan levels are not greatly influenced by processing conditions, resistant starch and sugar concentrations are susceptible to considerable changes with increasing processing temperature. This is useful in the potential utilization of plantain as a source of resistant starch and possibly fructo-oligosaccharides in functional food applications. |
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