Valorization of Bioactive Compounds from Two Underutilized Wild Fruits by Microencapsulation in Order to Formulate Value-Added Food Products

Abstract

Currently, microencapsulation has become a viable method of nutrient delivery for the food industry. This work microencapsulated the bioactive compounds extracted from two neglected species (Balanites aegyptiaca and Ziziphus mauritiana) by freeze-drying. A combination of wall materials (whey protein and pectin; soy protein and maltodextrin) was chosen to prepare the microcapsules. The phytochemical and physicochemical characterization of the microcapsules was then carried out. The encapsulation yield ranged from 82.77% to 96.05% for Balanites and Ziziphus, respectively, whereas the efficiency was 76.18 ± 1.39% and 80.93 ± 1.71%. The stimulated in vitro gastrointestinal test showed that encapsulation increased the bioavailability of the bioactive compounds. The total carotenoids were the most bioavailable compounds with 85.89 ± 0.06% for Ziziphus and 70.46 ± 1.10% for Balanites, followed by total flavonoids for Zizyphus with 63.27 ± 1.56%. Furthermore, regardless of species or wavelengths, the HPLC analysis resulted in the identification of 17 bioactive metabolites. The predominant one was epicatechin, whose level ranged from 231.52 ± 5.06 to 250.99 ± 3.72 mg/100 g DW in Ziziphus and 91.80 ± 3.85 to 116.40 ± 4.09 mg/100 g DW in Balanites. In estimating the enzyme inhibition and antioxidant power, both studied fruits showed antidiabetic, inflammatory, and antioxidant effects. These findings suggest that natural bioactive compounds are abundant in the fruits of Z. mauritiana and B. aegyptiaca and could be a valuable source for the food and pharmaceutical industries.

Keywords: Balanites aegyptiaca; Ziziphus mauritiana; biocompounds; microencapsulation.

Figure 1

Storage stability of TPC, TFC (A), DPPH, and ABTS (B) from the microencapsulated extracts of Ziziphus mauritiana. Different letters (a–c) for the same parameter show a significant difference between the means at 0.05.

Figure 2

Storage stability of TPC, TFC (A), DPPH, and ABTS (B) from the microencapsulated powder of Balanites aegyptiaca. Different letters (a–c) for the same parameter show a significant difference between the means at 0.05.

Figure 3

Structure of the powders obtained by Ziziphus mauritiana (a) and Balanites aegyptiaca (b) extracts microencapsulation.

Figure 4

TPC, TFC (A), TC (B), and antioxidant activity (C) release (%) after 2 h of in vitro gastric and intestinal digestion of Ziziphus mauritiana crude and microencapsulated extracts. MP: Microencapsulated powder; CP: Crude powder; TPC: Total polyphenolic contents; TFC: Total flavonoid contents; TC: Total carotenoids. For each biocompound, the gastric phase averages that do not share any lower-case letters are significantly different at the 0.05 threshold; the same applies to the averages of the intestinal phase that do not share any upper-case letters.

Figure 5

TPC, TFC (A), TC (B), and antioxidant activity (C) release (%) after 2 h of in vitro gastric and intestinal digestion of Balanites aegyptiaca crude and microencapsulated extracts. MP: Microencapsulated powder; CP: Crude powder; TPC: Total polyphenolic contents; TFC: Total flavonoid contents; TC: Total carotenoids. For each biocompound, the gastric phase averages that do not share any lower-case letters are significantly different at the 0.05 threshold; the same applies to the averages of the intestinal phase that do not share any upper-case letters.

Figure 5

TPC, TFC (A), TC (B), and antioxidant activity (C) release (%) after 2 h of in vitro gastric and intestinal digestion of Balanites aegyptiaca crude and microencapsulated extracts. MP: Microencapsulated powder; CP: Crude powder; TPC: Total polyphenolic contents; TFC: Total flavonoid contents; TC: Total carotenoids. For each biocompound, the gastric phase averages that do not share any lower-case letters are significantly different at the 0.05 threshold; the same applies to the averages of the intestinal phase that do not share any upper-case letters.

Figure 6

HPLC chromatogram for the flavonoids and polyphenols from Ziziphus mauritiana extract at 280 nm (a) and 320 nm (b). Peak identifications: (a) 2—Gallic acid, 3—Chlorogenic acid, 4—(-)—Epicatechin, 5—Caffeic acid, 8—Quercetin, 13—Isorhamnetin, 1, 6, 7, 9–12, and 14–17—unidentified peaks; (b) 3—(-)—Epicatechin, 4—Caffeic acid, 6—p-coumaric acid, 9—Quercetin, 1, 2, 5, 7, 8, and 10–15—unidentified peaks.

Figure 7

HPLC chromatogram for the flavonoids and polyphenols of Balanites aegyptiaca extract at 280 nm (a) and 320 nm (b). Peak identifications: (a) 2—Chlorogenic acid, 3—(-)—Epicatechin, 5—Caffeic acid, 1, 4, and 6–17—unidentified peaks; (b) 2—Chlorogenic acid, 3—(-)—Epicatechin, 5—Caffeic acid, 1, 4, and 6–13—unidentified peaks.