Harvest maturity and storage temperature affect fruit colour, chilling injury and quality of Indian gooseberry fruit (Emblica officinalis Gaertner)

摘要

Introduction - The climatic conditions during growing season affect fruit quality and storage behaviour of Indian gooseberries. The objective was to study the different harvest stages and storage temperatures in order to influence the storage quality of this fruit. Materials and methods - Fruit of the cultivar Neelum was harvested at three maturity stages, packed in plastic crates and stored at 6, 9 or 12 degrees C with 90-95% relative humidity, or at room temperature (RT). Commercial fruit quality traits were recorded along 12 days of storage (DOS): colour, firmness, weight loss (WL) and fruit spoilage. Sweetness and acidity were measured through soluble solid content (SSC) and titratable acidity (TA). Biochemical measurements were also performed on fruit juice: pH and ascorbic acid content. Results and discussion - The lightness (L*) and chromatic values increased, and the hue angle (h degrees) decreased with the storage period with no specific influence of the storage temperature. Fruit firmness declined from harvest to lowest levels at 12 DOS with minimum decrease at 9 degrees C. Lightness was negatively correlated with firmness and positively with WL and spoilage, while hue angle was positively correlated with firmness and negatively with WL and spoilage. The fruit from second and third harvest had higher L*, firmness; and lower spoilage and h degrees.The fruit harvested from second and third harvest showed lower WL over first harvest. The minimum WL during 12 DOS was recorded at 6 degrees C (5.52%) followed by 9 degrees C (6.70%). Chilling injury (CI) developed in shorter duration at 6 degrees C than 9 degrees C; no CI was observed at 12 degrees C. The sugars, SSC, SSC:TA and phenolics increased with storage interval, whereas TA decreased. Conclusion - In subtropical regions, Indian gooseberry fruit can be harvested 207-209 days after full bloom for a fortnight or till the daily mean temperatures remain >18 degrees C. The fruit quality parameters coinciding with the second harvest viz. dry matter, firmness levels and SSC:TA ratio can be considered as the reference.