The Effect of One-Year Fermentation of Maesil Fruit (Prunus mume) Sugar Syrup on Amygdalin Level: A Natural Toxic Compound

<i>Prunus mume</i> (<i>maesil</i>) is an economically important fruit in Korea. Recently, public interest in <i>maesil</i> sugar syrup is increasing. However, the presence of toxic amygdalin in the fruit syrup is a concern. Thus, the current investigation aimed to observe effects of <i>maesil</i> maturity, ripening methods, processing, and fermentation period on the amygdalin level in <i>maesil</i> sugar syrup. Six different types of <i>maesil</i> sugar syrup were prepared and amygdalin content was monitored at 3-month intervals. Higher levels (>63 mg/L) of amygdalin were found in syrups prepared from unripe fruit compared to those in syrups made from ripe fruit after 3 months of fermentation. A rapid reduction in amygdalin content was observed until 9 months in all syrups, gradually reducing to <5 mg/L at 12 months. More than 9 months of maturation is crucial for reducing the amygdalin content <i>maesil</i> sugar syrup, regardless of fruit maturity, source of fruit, and processing method.