Determination of Amygdalin in Apple Seeds, Fresh Apples and the Processed Apple Juices 2

6 7 8 9 Abstract 10 Cyanogenic glycosides are natural plant toxicants. Action by endogenous plant enzymes 11 can release hydrogen cyanide causing potential toxicity issues for animals including 12 humans. We have quantified amygdalin in seeds from different apple varieties, determined 13 the effects of processing on the amygdalin content of apple juice and quantified amygdalin 14 in commercially-available apple juices. Amygdalin contents of seeds from fifteen varieties of 15 apples ranged from 1 mg g-1 to 4 mg g-1. The amygdalin content of commercially-available 16 apple juice was low, ranging from 0.01 to 0.04 mg ml-1 for pressed apple juice and 0.001 to 17 0.007 mg ml-1 for long-life apple juice. Processing led to juice with low amygdalin content, 18 ranging from 0.01 mg ml-1 to 0.08 mg ml-1. The results presented show that the amygdalin 19 contents of commercially-available apple juices are unlikely to present health problems to 20 consumers. 24 25 26 27 22 Introduction 28 Apple (Malus domestica) is a member of the Rosaceae family that also includes 29 apricots, cherry, peaches, pear and plum and is the most widely consumed fruit in the UK. 30 World apple production in 2011/12 was estimated to be 65.23 million metric tons, out of 31 which 12.2 million metric tons was used for the production of apple juice (Negro & Lojo, 32 2011). Although apple contains compounds which may confer significant health benefits to 33 humans, apple seeds contain amygdalin (Fig.1), a potentially toxigenic compound. 34 Commercial apple juice is usually made from a blend of apples to produce an 35 acceptable juice in terms of flavour. Apples are soaked in water to remove soil and other 36 foreign material. The cleaned apples are then inspected, and damaged or decayed fruit 37 should be removed to avoid patulin contamination from the final product. The sorted 38 apples are ground into mash or pulp for extraction, crushing or cutting the apples to 39 appropriate consistency. The mashed apples are pressed by applying pressure to obtain 40 the juice. In some cases, enzymatic mash treatment is used to improve the pressability of 41 the mash and increase juice yield, achieved by adding a pectinase enzyme such as 42 pectinol specifically developed for apple mash pre-treatment. The enzyme acts mainly by 43 breaking down the structure of the cell wall, thus freeing the juice. 44 Cyanogenic glycosides, including amygdalin, are naturally-occurring …