Isolation and characterization of naringinase enzyme and its application in debittering of Pomelo juice ( Citrus grandis ): A comparative study with macroporous resin

Abstract

The naringinase enzyme was isolated from Citrus macroptera peel and pomace using Aspergillus niger for immobilization and debittering of juice. A comparative study of the effect of debittering using immobilized enzyme and resin on the physicochemical and phytochemical properties of the juice were carried out. The optimum hydrolytic conditions and Michaelis constant for an immobilized enzyme were observed at pH 4, 70℃, and 16.75 μg/ml, respectively. Adsorption of naringin onto resin followed pseudo-first-order with a regression coefficient of 0.92. Naringin content was reduced up to 73.28% in 4 min by resin and 79.76% in 120 min by the enzyme. We reutilized resin and immobilized enzyme effectively to debitter the juice up to seven cycles. Treatment for less than 2 min and 90-120 min using resin and enzyme, respectively, could retain the sizable amount of bioactive components in juice and immobilization retained 62% enzymatic activity during 2 months of storage at 4°C. Practical applicationsPomelo being a rich source of bioactive nutrients faces slow commercialization due to immediate bitterness (naringin), thus in the present study, Citrus macroptera waste including peel and pomace was efficiently utilized to produce naringinase enzyme for the debittering of pomelo juice. Also, adsorption kinetics of naringin using macroporous resin is presented, which will further help in the selection of optimum time and dose for the removal of naringin from the juice. More importantly, their effect on juice composition helped in the selection of the potential candidate for the industrial purpose with negligible or minimum loss of nutrients.

Ultrasound aided debittering of bitter variety of citrus fruit juice: Effect on chemical, volatile profile and antioxidative potential

“…The enzyme was purified, characterised, and kept at 4 °C for the debittering test as described in our earlier study [62] . In a conical flask, freshly extracted juice (100 mL) was combined with 2 mL enzyme (52.8 U/mL activity) and 2 mL phosphate buffer solution (pH 7.20) and treated at optimal frequency (10–50 kHz), time (0–120 min), and temperature (20–70 °C).…”

“…Resin-based physical adsorption and enzyme- or bacteria-based bioconversion ( [43] , [58] , [62] ) were employed for debittering of citrus juice. Physical adsorption considerably reduced the bitterness and bioactive compounds in orange juice [46] .…”

Design and development of laboratory scale batch type device for debittering of bitter citrus juice

“…The loss was attributed to the inactivation of the enzyme at high temperatures, because little leakage of the enzyme was observed during the initial cycles, indicating that the enzyme was firmly bound to the support. We also compared the stability with our previous study (Gupta, Yumnam, et al, 2021), where the stability of alginate immobilized enzymes decreased with repeated usage. The low solubility of naringin and the stability of adsorbed enzymes are still challenges for food scientists and the juice processing industries in the application of such devices for efficient debittering.…”

“…As indicated in our earlier work, the enzyme was extracted, purified, and characterized (Gupta, Yumnam, et al, 2021). The protein content of the purified enzyme was measured using a standard procedure, and the activity of naringinase was assessed by Busto et al (2007).…”

“…From the illustration, the negative effect of the enzyme-resin device Researchers in the past have also found that ascorbic acid is lost during the enzymatic debittering of citrus juice (Gupta, Yumnam, et al, 2021;Mishra & Kar, 2003;Stinco et al, 2013).…”