Optimization of pectin extraction from selected Philippine fruit peel wastes using Box-Behnken design

Abstract

Background: Pectin is a pharmaceutically relevant excipient that can be upcycled from selected Philippine fruit peel wastes. Method optimization of pectin extraction leads to maximizing yields from limited resources, while also reducing environmental wastes, and providing local alternative sources.

Objectives: This study aimed to optimize the method of extracting pectin from selected Philippine fruit peel wastes using the Box-Behnken design, by varying the acid extraction solvent, treatment time, and working temperature.

Methodology: The three-level (-1, 0, 1) Box-Behnken design (15 set-ups) was used to optimize the pectin extraction in each of the fruit peel samples (C. maxima; A. heterophyllus; ripe and unripe M. indica; D. zibethinus; and H. undatus). The three experimental factors were the type of 3N acid used as extracting solvent (HNO₃, H₂SO₄, and HCl); duration of treatment in minutes (60, 90, and 120); and temperature of treatment in C 60, 75, and 90). The %yield was computed in each set-up, and the projected yields were generated using multiple linear regression. The pectin samples obtained from the optimized conditions were subjected to the physicochemical characterization, with apple pectin as the standard. Degree of esterification (DE), equivalent weight (EW), methoxy content (MC), alkalinity of ash (AA), and anhydrouronic acid content (AUA) were performed.

Results:Maximum yields were extracted from C. maxima (28.96%), A. heterophyllus (20.12%), ripe M. indica (26.23%), and unripe M. indica (25.89%), using 3N H₂SO₄, for a treatment duration of 60 minutes, at a working temperature of 90 C, and H. undatus (25.03%) at 60 C, for a treatment duration of 120 minutes.

Conclusion: Optimum conditions were identified to extract pectin in each of the fruit peel samples. The 3N H₂SO₄ produced the highest pectin yields in all of the set-ups, while the treatment time and working temperature vary per fruit peel sample. Pectin extract from C. maxima, A. heterophyllus, and M. indica was comparable to the standard.