Potential of jackfruit inner skin fibre for encapsulation of probiotics on their stability against adverse conditions

Abstract

The aim of this study was to investigate the impact of jackfruit inner skin fibre (JS) incorporated with whey protein isolate (WPI) and soybean oil (SO) as a wall material for probiotic encapsulation to improve probiotic stability against freeze-drying and gastrointestinal (GI) tract conditions. Bifidobacterium bifidum TISTR2129, Bifidobacterium breve TISTR2130, and Lactobacillus acidophilus TISTR1338 were studied in terms of SCFA production and the antibiotic-resistant profile and in an antagonistic assay to select suitable strains for preparing a probiotic cocktail, which was then encapsulated. The results revealed that B. breve and L. acidophilus can be used effectively as core materials. JS showed the most influential effect on protecting probiotics from freeze-drying. WPI:SO:JS at a ratio of 3.9:2.4:3.7 was the optimized wall material, which provided an ideal formulation with 83.1 ± 6.1% encapsulation efficiency. This formulation presented > 50% probiotic survival after exposure to gastro-intestinal tract conditions. Up to 77.8 ± 0.1% of the encapsulated probiotics survived after 8 weeks of storage at refrigeration temperature. This study highlights a process and formulation to encapsulate probiotics for use as food supplements that could provide benefits to human health as well as an alternative approach to reduce agricultural waste by increasing the value of jackfruit inner skin.

Figure 1

Acetic acid production of B. bifidum, B. breve, and L. acidophilus at days 1, 3, and 5 of incubation at 37 °C. Bars represent the mean standard deviation. Different lowercase letters indicate significant differences (P < 0.05) among incubation periods of each probiotic strain.

Figure 2

Mixture response surface contour plots displaying the combined effect of whey protein isolate (WPI), soybean oil (SO), and inner skin of jackfruit fibre (JS) on probiotic survivability recovered from dry powder after freeze-drying.

Figure 3

Characteristic of encapsulated probiotics with different wall materials formulated with various ratios of whey protein isolate (WPI), soybean oil (SO), and jackfruit inner skin fibre (JS).

Figure 4

Scanning electron microscopic photographs at 2000× magnification of encapsulated probiotics. WPI-SO (A); encapsulated probiotics with whey protein isolate and soybean oil at 1:1 ratio, JS-SO (B); encapsulated probiotics with jackfruit inner skin fibre and soybean oil at 1:1 ratio, Optimal formulation (C); encapsulated probiotics with whey protein isolate, soybean oil, and jackfruit inner skin fibre at 3.9:2.4:3.7 ratio.

Figure 5

Survivability of encapsulated probiotics with optimal formulation under stimulated continuous gastro-intestinal tract in-vitro compared to WPI-SO formulation, and free cells. Bars represent the mean standard deviation. ^a,b,c indicated significant differences (P < 0.05) between the sample in gastric digestion condition. ^A,B,C indicated significant differences (P < 0.05) between the sample in intestinal digestion condition.

Figure 6

Stability of encapsulated probiotics kept in aluminium-laminated foil bags at ambient temperature (28 ± 2 °C) and refrigeration temperature (6 ± 2 °C) for 8 weeks.