Impact of Processing and Intestinal Conditions on in Vitro Digestion of Chia (Salvia hispanica) Seeds and Derivatives

Abstract

Chia seeds present with an excellent nutrient profile, including polyunsaturated fat, protein, fibre and bioactive compounds, which make them a potential food or ingredient to bring beneficial health effects. However, their tough structure could mean that these seeds remain hardly disrupted during digestion, thus preventing the release and digestibility of nutrients. In the present study, different chia products (seeds, whole flour, partially defatted flour and sprouts) were assessed in terms of proteolysis, lipolysis, calcium and polyphenols bioaccessibility and antioxidant activity. In vitro digestions were performed supporting standard intestinal (pH 7, bile salts concentration 10 mM) and altered (pH 6, bile salts concentration 1 mM) conditions. The altered conditions significantly reduced lipolysis, but not proteolysis. Regarding the food matrix, compared to the chia seeds, whole and partially defatted flour increased the hydrolysis of lipids and protein, relating to reduced particle size. Sprouting had an enhancing effect on proteolysis but prevented lipolysis. Calcium bioaccessibility dropped in all the samples in the two intestinal conditions. The digestion process led to increased polyphenols bioaccessibility in all the structures, but reduced antioxidant activity except in the milled structures. In conclusion, milling should be applied to chia seeds prior to consumption in cases where enhancing the potential uptake of macro and micronutrients is targeted, and sprouting is suitable to enhance protein digestibility and reduce lipolysis.

Keywords: antioxidant activity; chia; chia flour; chia seeds; in vitro digestion; lipolysis; milling; pancreatic insufficiency; proteolysis; sprouting.

Figure 1

Particle size distributions of the chia seeds and chia flours imparted by the mechanical process and the simulated mastication. d_3,2 values sharing a same letter are not significantly different (p < 0.05) (data are expressed as mean values from three repetitions).

Figure 2

Milling process of chia seeds reduces particle size, which significantly increases lipid and protein digestibility in chia flours as compared to chia seeds (after simulation of mastication) (data are expressed as mean values from three repetitions).

Figure 3

Lipid (A) and protein (B) digestibility in chia seeds, whole chia flour, partially defatted chia flour and chia sprouts during the gastric and standard (pH 7, bile salts concentration 10 mM) and altered (pH 6, bile salts concentration 1 mM) intestinal conditions. ND = non-detectable. Different capital letters (A–D) mean significant differences (p < 0.05) between chia products (chia seeds, whole chia flour, partially defatted chia flour and chia spouts). Different lowercase letters (a, b) means significant differences (p < 0.05) between intestinal conditions (standard and alternated) (data are expressed as mean values from three repetitions and the error bars represent the standard deviation).