Abstract:

To improve the usability of upper tobacco leaves, it is necessary to explore the suitable roasting method and number of left leaves of upper tobacco. Using ‘Yunyan 87’ as the test material, the effects of two harvesting methods, namely upper tobacco with stem and leaf by leaf harvesting, with 3 leaves (BJ3, BZ3), 4 leaves (BJ4, BZ4), 5 leaves (BJ5, BZ5), and 6 leaves (BJ6, BZ6), on the economic characteristics and leaf quality of cured tobacco were studied. Research showed that the proportion, average price, appearance quality, coordination of main chemical components, and sensory quality of cured tobacco harvested with stems were generally better than those harvested leaf by leaf. The proportion and average price of top grade tobacco were highest in BJ4, followed by BJ5, and a significant difference was observed in the harvesting of upper tobacco with stems; those of BZ4 was the highest in leaf by leaf harvesting, followed by BZ5, and BJ4 increased by 9.11 percentage points and 0.80 yuan/kg respectively compared with BZ4, BJ5 increased by 5.10 percentage points and 0.14 yuan/kg respectively compared with BZ5. The total score of appearance quality was highest in BJ5, followed by BJ4. BZ5 was the highest in leaf by leaf harvesting. The main chemical components included reducing sugars, total sugar content, and sugar to alkali ratio, which were more suitable for BJ4 in harvesting with stems, followed by BJ5, and BZ5 were more suitable for harvesting leaf by leaf. The total score of sensory evaluation for smoking quality of BJ5 in harvesting with stems was the highest, which was 76.40 points, and those of BZ5 in leaf by leaf harvesting was the highest, which was 74.90 points. The grade structure and intrinsic quality of tobacco leaves harvested with stems from 4-5 upper tobacco leaves are better than those harvested leaf by leaf.

Key words: upper tobacco leaves, harvesting method, number of left leaves, tobacco quality, usability, economic traits