Comparative Study on Quality, Physiological Indexes and Aroma Components among Mulberry Varieties

Six mulberry varieties in Shandong Province were used to investigate their quality, physiological properties and volatile aroma components by sensory evaluation, physicochemical analysis and gas chromatography-mass spectrometry techniques. The results showed that “Baiyuwang” and “Dashi” had the highest weight and shape index. “Heizhenzhu”and “Moyu” appeared the highest hardness (3.32, 2.67 kg/cm2) and solid-acid ratio (92.87, 82.76), as well as higher polygalacturonase (PG) and lipoxygenase (LOX) activity. But the higher juice yield (63.32%, 61.19%) was found in “Moyu” and “Dashi”. In addition, “Dashi” and “Hongguo” had higher anthocyanin (0.58, 0.53 mg/g), total phenolic content (2.48, 2.59 mg/g), strong DPPH and ABTS+ free radical scavenging ability, followed by “Longguai”, “Moyu” and “Heizhenzhu”, while “Baiyuwang” was the lowest in anthocyanin and total phenolic. The analysis of volatile aroma components showed that “Moyu” had the most aroma species and reached 62, followed by “Dashi” and “Baiyuwang”. Among them, the aroma components of “Heizhenzhu” and “Dashi” were mainly alcohols, however, “Moyu”, “Longguai” and “Baiyuwang” were mainly aldehydes, ketones and olefins. The common aroma components of the six varieties were mainly 2-amino-6-methylbenzoic acid and hexanal. The study provides a reference for the quality evaluation, processing and utilization of mulberry varieties.