不同成熟度对散叶生菜采后生理品质的影响

Effects of Maturity on Postharvest Physiology and Quality of Leaf Lettuce

[目的]研究不同的采收成熟度对散叶生菜采后生理品质的影响。[方法]通过对生菜采后贮藏期间的失重率、含水量、呼吸强度、VC、叶绿素等理化指标和感官指标的测定,以及对散叶生菜不同成熟度指标的规定,研究未成熟、成熟和过熟3种不同成熟度对生菜采后生理品质的影响。[结果]试验表明,成熟和过熟的生菜衰减率低于未成熟的生菜,成熟和未成熟生菜的褐变及腐烂程度低于过熟生菜。未成熟生菜易失水失重,贮存至第9天时,失重率较过熟生菜高11.69%,失水率高于过熟生菜7.11%。过熟生菜易脱色,贮存至第9天时,叶绿素下降率高于未成熟生菜17%左右。过熟生菜容易受到机械损伤,出现黄褐色斑点、褐变、腐烂和其他生理疾病,且具有强烈的苦味和韧性,严重影响产品品质;成熟生菜相对未成熟生菜不易损伤且叶片呼吸速率相对较低,低于未成熟生菜约26mg/(kg·h);成熟生菜相对过熟生菜贮期可延长3 d,相对未成熟生菜贮藏期可延长2 d,产量高,各质量指标最为理想。[结论]试验建议根据成熟度标准考虑适时采收,选择优质的成熟生菜以保证最大经济效益以及最优的生菜质量。

[ Objective ] To study effects of different harvesting maturity degree on lettuce postharvest physiological quality. [ Method ] This pa- per studied the effects of immature, mature, overmature, 3 different maturity on lettuce postharvest physiological quality by deal with the deter- mination of lettuce weight loss rate, water content, respiratory intensity, Vc, chlorophyll and other physicochemical index and sensory indexes during postharvest storage, and the provisions of leaf lettuce different maturity index. [ Result] The results showed that： the mature and over- mature lettuce decay rate is lower than the immature lettuce. Mature and immature lettuce browning and decay degree is lower than overmature lettuce. Immature lettuce is easy to lose water and weight, the weight loss rate is 11.69% higher than the overmature lettuce and water loss rate is 7.11% higher than the overmature lettuce after storaged for 9 days. Overmature lettuce is easy to decolour, chlorophyll decreased rate is about 17% higher than that of immature lettuce after storaged for 9 days. Overmature lettuce susceptible to mechanical injury, appear brown spots, browning, decay and other physiological disease, and have a strong bitter taste and toughness, seriously affect the product quality. The mature lettuce is not easy to damage relatively than immature lettuce and leaf respiration rate is about 26 mg/（ kg . h） lower than immature let- tuce. The storage period of mature lettuce may be extended for 3 days than overmature lettuce, and may be extended for 2 days than immature lettuce, it has a high yield and each quality index is the most ideal. [ Conclusion ] Harvesting at proper time according to maturity degree and selecting high quality maturity lettuce was suggested, so as to guarantee the maximum economic benefit and the optimal quality of lettuce.