Macroporous adsorbent resin debittering of Huang long bing (HLB)-affected orange juice and its impacts on consumer sensory acceptance

Abstract

Huang long bing (HLB) infection of oranges induces the biosynthesis and accumulation of bitter limonoids. The objective of this study was to debitter HLB-affected orange juice while preserving the tasteless and health-promoting limonoid glucoside and flavanones using resin adsorption. Three resins (FPX66, PAD900, and XAD16N) were found to have higher adsorption and desorption capacity for limonin among seven selected resins. Adsorption of limonoids rapidly increased in the first 2 h of kinetic tests, while slower adsorption kinetics were observed for flavanones. Limonin isothermal adsorption fit best with the Langmuir model, suggesting a physical, monolayer process. Dynamic adsorption showed that a fixed-bed column packed with PAD900 was able to debitter 200 bed volumes of orange juice before limonin reached its taste threshold of 4.7 µg/mL in the eluent. The resin was regenerated by eluting the column with four bed volumes of alcohol or 4% NaOH to remove adsorbed compounds from the resin. Resin adsorption reduced limonin content in orange juice from 5.85 to 1.34 µg/mL but also decreased tasteless compounds by at least 40%. A consumer sensory test gave the debittered juice a higher overall liking and preference over untreated juice. This study showed that resin adsorption is an effective approach to reduce the bitterness of orange juice affected by HLB.