The study was initiated to optimize the enzymabtic extraction process of plantain pulp using response surface methodology. Weight loss of plantain decreased until it became stable at an over-ripe stage. The significant regression model describing the changes of extraction yield and Brix with respect to hydrolysis parameters was established. Temperature contributed to reducing the yield from 53.52% down to 49.43%, and the dilution factor increased the yield from 53.52% to 92.97%. On the contrary, the dilution factor significantly reduced Brix from 21.74 • Bx down to 0.15 • Bx, while the enzyme concentration increased Brix from 21.73 • Bx to 26.16 • Bx. The optimum conditions for juice extraction from plantain pulp were: temperature: 25 • C; enzyme concentration: 5%; dilution ratio: 1.10; and extraction time: 24 h. The implementation of these conditions led to (resulted in obtaining) obtaining a must yield of more than 70% and Brix between 10 • Bx and 15 • Bx. The total polyphenols and flavonoids were 7.70 ± 0.99 mg GAE /100 g and 0.4 ± 0.01 µg rutin/g for must and 17.01 ± 0.34 mg GAE/100 g and 4 ± 0.12 µg rutin/g and 7.70 ± 0.99 for wine, indicated the presence of antioxidant activity in the produced wine. On the other hand, the total soluble solids were between 16.06 ± 0.58 • Bx and 1.5 ± 0.10 • Bx, which permitted obtaining a wine with low alcohol content.

BACKGROUND: Soursop (Annona muricata L.) is an underutilized tropical and subtropical fruit with high nutritional and therapeutic benefits. This fruit is faced with enormous post-harvest losses due to its high perishability. This work was aimed to optimize the pectinase-assisted extraction conditions of soursop juice using Doehlert design and to study the effect of pectinase on its pectin structure. RESULTS: The predicted models were validated for all the responses studied and the regression coefficients ranged from 0.905 to 0.987 (P ≤ 0.05). An incubation time of 172 min, enzyme concentration of 0.04% (w/w) and incubation temperature at 42.9°C were found to be the optimal conditions for soursop juice extraction, which resulted in 75.20%, 3.74, 7.35°Brix, 87.06%T, and 0.44% MAE for soursop juice yield (%), pH, total soluble solids (TSS) (°Brix), clarity (%T) and titratable acidity (% malic acid equivalent, MAE), respectively. Morphologically, untreated soursop pulp presented a non-uniform spherical surface; enzyme hydrolyzed soursop exhibited ruptured and wrinkled surface; meanwhile for the different pectin obtained, untreated soursop pectin depicted porous surface and enzyme hydrolyzed soursop pectin showed whirling rough surface. Fourier-transform infrared (FTIR) confirmed the presence of similar chemical group stretching and vibrations in commercial pectin and soursop pectin. CONCLUSION: Under the optimum conditions, the numerical predictions were similar to the experimental data obtained, thus confirming the validity of the models. Application of enzyme treatment caused the breakdown of pectin structure as illustrated by scanning electron microscopy (SEM) and FTIR analyses. Supporting information may be found in the online version of this article.

Pickering emulsion of red palm oil (RPO) with pectin as stabilizer was optimized using response surface methodology (RSM). RSM parameters for final red palm oil pickering emulsion (RPE) were 3% pectin, 30% RPO, and homogenization speed of 24,000 rpm for 15 min. RPE was subjected to physicochemical characterizations, along with storage studies for 15 days. Microstructure imaging of RPE confirmed pickering emulsion formation. Droplet diameter and zeta potential of RPE were 1.779 μm and −32.5 mV, respectively. Fourier transform infrared spectroscopy of RPE suggested hydrogen bonding interactions between the components, and thermogravimetric analysis revealed stability up to 40°C. Gastrointestinal bioaccessibility of naturally occurring β‐carotene in the RPE (37.76 ± 1.2%) was found to be four times higher than that of RPO (8.7 ± 0.8%). The RPE was more stable at 4°C as indicated by storage analyses. RPE can improve the bioaccessibility of nutritionally important bioactive compounds. Practical applications Pickering emulsions of RPO stabilized by pectin can be used for developing functional foods with improved bioaccessibility of lipophilic bioactives such as carotenoids as well as for the delivery of temperature sensitive nutritional and bioactive compounds. These emulsions can also be found applications in beverages, low temperature processed foods and vegan fat substitutes.