The effect of agar-pectin gels on the eating behaviour of fasted and fed mice

Abstract

A diet rich in non-digestible plant polysaccharides (dietary fibers) leads to effective appetite suppression and reduces food intake. The mechanical properties of food contribute to the satiating effect of food. It is known that solid food satiates to a greater extent than liquid, as the duration of food processing in the oral cavity increases. The aim of the study was to assess the effect of mechanical properties of agar-pectin gels on the feeding behaviour of mice Material and methods. The gels were prepared by dissolving the corresponding weights of agar, pectin and sucrose in 100 ml of water: gel 1 contained 6 g of agar, 3 g of pectin, gel 2 - 20 g of agar, 1 g of pectin and 0.03 M CaCl2, gel 3 - 20 g of agar, 1 g of pectin (without the addition of calcium ions). All gels contained an equal amount of sucrose (15 g per 100 ml of water). The mechanical properties of the gels (strength, Young's modulus and elasticity) were determined on a texture analyzer. Mice with an initial body weight of 32.9±0.5 g (n=8 in each group) received gels once a day for four days. Each day, animals were individually placed in experimental cages for 60 minutes: in the first 30 min, they were given test gels and for the next 30 min standard rodent food. The first two days were training. Before the third gel presentation, the animals were previously completely restricted in food for 14 hr (fasted mice), and before the fourth gel presentation, the mice received food ad libitum (fed mice). The eating behaviour of the mice, the amount of gel eaten and standard feed eaten were determined. Mice that were not exposed to gels were used as control. Results and discussion. Gel 3 was the hardest (251±3 kPa) in comparison with gel 1 (44±1 kPa) and 2 (141±3 kPa). Fasted mice that received gel 3 ate 36% less food (p<0.05), and the total energy intake was 19% lower (p<0.05) compared to the control. Fasted mice that received gels 1 and 2 ate the same amount of food as the control animals. Gel 3 significantly reduced feeding time by 19% (p<0.05) in fasted mice. Gels 1 and 2 did not alter the eating behaviour of fasted mice. Fed mice that received gels ate as much food as in the control. Gels failed to affect the eating behaviour of fed mice. Conclusion. Overall, solid gel 3 reduced food intake and time spent on feeding after 14 h of complete food restriction. The effect of the gel on the feeding behaviour of animals and the amount of food eaten is determined by the hardness of the gel and does not depend on the ratio of the components of the gel and its resistance to in vitro simulated gastric and intestinal fluids.