Biscuits with No Added Sugar Containing Stevia, Coffee Fibre and Fructooligosaccharides Modifies α-Glucosidase Activity and the Release of GLP-1 from HuTu-80 Cells and Serotonin from Caco-2 Cells after In Vitro Digestion

Abstract

This study assessed the in vitro effects of the bioaccessible food components released during the simulated human digestion of a coffee fibre-containing biscuit (CFB) on α-glucosidase activity, antioxidant capacity and satiety hormones. Digest of CFB presented a significantly (p < 0.05) lower amount of sugar (68.6 mg/g) and a higher antioxidant capacity (15.1 mg chlorogenic acid eq./g) than that of a sucrose-containing biscuit (SCB). The CFB significantly reduced (p < 0.05) α-glucosidase activity (IC50 = 3.3 mg/mL) compared to the SCB (IC50 = 6.2 mg/mL). Serotonin and glucagon-like peptide-1 (GLP-1) release by differentiated Caco-2 and HuTu-80 cells, respectively, was stimulated by the CFB (355% at a concentration of 0.5 mg/mL and 278% at a concentration of 0.05 mg/mL) to the same order of magnitude as those of the SCB. To summarize, the CFB was demonstrated to reduce monosaccharide bioaccessibility, to inhibit a diabetes-related digestive enzyme, and to improve the release of satiety hormones.

Keywords: GLP-1; biscuits; coffee fibre; fructoologosaccharides; non-nutritive sweeteners; serotonin; stevia; α-glucosidase.

Figure 1

Effect on α-glucosidase activity is represented by dose-response curves of (a) acarbose (0.1 μg/mL–30 mg/mL); (b) soluble fractions recovered from the digested sucrose-containing biscuit (SCB) (0.5–100 mg/mL), coffee fibre-containing biscuit (CFB) (0.01–100 mg/mL) and stevia (0.05–200 mg/mL); and (c) soluble fractions recovered from the digested coffee fibre (0.5–1000 mg/mL) and FOS (0.5–2000 mg/mL). Values represent mean ± standard deviation. This includes a duplicate of sample preparation and a triplicate of analysis (n = 6).

Figure 2

Serotonin release after stimulation of Caco-2 cells at 0.5, 0.05 and 0.01 mg/mL with soluble fractions recovered from the digested sucrose-containing biscuit (SCB), coffee fibre-containing biscuit (CFB) and antioxidant coffee fibre that contain bioaccessible compounds, as well as stevia. Results are displayed as T/C in percent compared to the control (cells with media = 100%). All measurements were expressed as mean ± SEM (n = 3, tr = 6). Significant differences between treatments were tested with one-way ANOVA followed by the Holm–Sidak post-hoc test (p < 0.05) and marked with the letters a, b and c.

Figure 3

Glucagon-like peptide-1 (GLP-1) release after stimulation of HuTu-80 cells at 0.5, 0.05 and 0.01 mg/mL soluble fractions recovered from the digested sucrose containing biscuit (SCB), coffee fibre containing biscuit (CFB) and antioxidant coffee fibre that contain bioaccessible compounds, as well as stevia. Results are displayed as T/C in percent compared to control (cells with media = 100%). All measurements were expressed as mean ± SEM (n = 3, tr = 6). Significant differences between treatments were tested with one-way ANOVA followed by the Holm–Sidak post-hoc test (p < 0.05) and marked with the letters a, b, c, d and e.