De-bittering studies of kinnow mandarin (Citrus reticulata Blanco) juice y

Abstract

Aim: The aim of the present study was to evaluate the presence of bittering factors limonin and naringin in kinnow fruits and to elucidate the process of kinnow juice de-bittering. Methodology: Limonin and naringin concentration was quantified using reverse phase HPLC. Both the constituents were evaluated in various compartments of fruits viz. seeds, albedo, flavedo, pomace and juice. The extracted kinnow juice was assessed for bittering factors during various months of harvesting, as well as during storage with variable pH (3, 4, 5) and temperature (low and ambient). Further, various adsorbents were tried on juice to adsorb limonin and naringin in order to elucidate the process of kinnow juice de-bittering. Results: Limonin and naringin were found to be the highest in seed and albedo portions. The level of limonin decreased with increasing pH and with low ne temperature storage comparatively. XAD-7 and XAD-16 were found to be at par as well as the most effective adsorbents in reducing bitterness compared to rest of the adsorbents tested. Interpretation: A process has been devised which involves manual removal of peel and seeds followed by treatment of extracted juice with centrifugation and activated carbon to reduce bittering constituents below their threshold levels in the final juice. The process does not require complex set-up of equipment and costly adsorbents.