ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Harvest indices, storability, and poststorage refrigeration requirement of 'Sunrise' apple.

Lau, O.L. and Lane, W. D.

HortScience : Vol: 33 Issue: 2 Pages: 302-304.

1998

บทคัดย่อ

Starch index and seed color are useful harvest indices for 'Sunrise' apple (Malus x domestica Borkh.). Increases in starch index value (approximately 1.4 units per week) and percent brown seed color (approximately 27% per week) were linearly correlated with harvest time and paralleled the increase in percent ripe fruit. 'Sunrise' was best picked, within a 1-week harvest window, at starch index values between 2.5 and 3.5 on a 0-9 scale, percent brown seed color of 30% to 50%, and flesh firmness of 69 to 73 N. Firmness loss was comparable to other apple cultivars during harvest (approximately 5 N per week) and during air or CA storage. However, 'Sunrise' fruit lost 18 to 27 N firmness during a 7-d 20 degrees C poststorage shelf-life test, resulting in fruit that was well below 49 N, the minimal firmness for consumer acceptance. Fruit previously stored at 0 degrees C had a shelf-life of 3 to 4 d at 20 degrees C, even though the fruit was picked at the correct maturity and had 70 to 74 N firmness at the end of storage. To ensure good eating quality, fruit must be held continuously at 0 degrees C until consumption. Firmness loss during shelf-life tests was higher for fruit harvested at starch index values between 1.3 and 2.4 and held in 0 degree air for 3 to 12 d (13 to 24 N firmness drop) than for fruit left on the tree and harvested at starch index 2.9 (10 N firmness drop). Fruit held in storage for 1 to 3 months were susceptible to flesh browning, flesh breakdown, core browning, stem-end browning, and storage rots. Early-picked (starch index <2.4) fruit held in CA for 1 month developed skin disorders resembling those of CO2 injury and scald.