METHODS: In a randomised, controlled crossover trial, ten healthy human subjects (five men, five women) were given 50 g glucose (reference food, twice); buns (0 and 10 % fenugreek seed powder); and flatbreads (0 and 10 % fenugreek seed powder) on six different occasions. Finger prick capillary blood samples were collected at 0, 15, 30, 45, 60, 90 and 120 min after the start of the meal. The palatability of the test meals was scored using Likert scales.
RESULTS: The incremental areas under the glucose curve value of buns and flatbreads with 10 % fenugreek (138 ± 17 mmol × min/L; 121 ± 16 mmol × min/L) were significantly lower than those of 0 % fenugreek bun and flatbreads (227 ± 15 mmol × min/L; 174 ± 14 mmol × min/L, P = <0.01). Adding 10 % fenugreek seed powder reduced the GI of buns from 82 ± 5 to 51 ± 7 (P
RESULTS: PPF was subjected to alkali and bleach treatment prior to hydrolysis, which successfully removed 54% and 75% of non-cellulosic components (hemicellulose and lignin, respectively). Hydrolysis conditions of 5 h, 15:1 (w/w) resin-to-pulp ratio and 50 °C produced CNC particles of 50-100 nm in length. CNC had a crystallinity index of 42% and appeared rod-like morphologically. CNC-stabilised emulsion had better stability when used in combination with soy lecithin (SL), a well-established, commonly used food stabiliser. Emulsion stabilised by the binary mixture of CNC and SL had droplet size, morphology and physical stability comparable to those of emulsion stabilised using SL.
CONCLUSIONS: CNC was successfully isolated from PPF through a cation exchange resin. This offers an alternative usage for the underutilised PPF to be converted into value-added products. Isolated CNC was also found to have promising potential in the stabilisation of Pickering emulsions. These results provide useful information indicating CNC as a natural and sustainable stabiliser for food, cosmeceutical and pharmaceutical applications. © 2021 Society of Chemical Industry.
RESULTS: Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions.
CONCLUSION: These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.