MSc

The experiment entitled “Postharvest management practices in pineapple (Ananas comosus (L.) Merr.)” was conducted at the Department of Post Harvest Technology, College of Agriculture, Vellayani, during the year 2018-2020, with the objective to standardize the post-harvest management practices in pineapple for improved fruit quality. The experiment was conducted separately for two maturity stages viz., stage1 (0- 25% eyes predominantly yellow) and stage 2 (25-50% eyes predominantly yellow) meant for distant and local markets respectively.
The study was conducted as two continuous experiments. In the first part, harvested pineapple fruits were subjected to four different pre-treatments viz., dipping in hot water of 50±20C for 1 minute, hydro cooling for 5 minutes, sanitization with 30 ppm sodium hypochlorite solution for 10 minutes and ozonisation with 2 ppm ozone for 15 minutes. The treated fruits along with untreated fruits were evaluated for the effects of pre-treatments on shelf life, physiological loss in weight and microbial load of pineapple fruits for selection of the best pre-treatment.
All the pre-treatments resulted in enhanced shelf life, reduced physiological loss in weight and low microbial load on pineapple fruit surface. Pineapple fruits of stage1 and stage 2 maturity, when subjected to hot water dip at 50±20C for one minute had maximum mean shelf life of 15.2 and 12.6 days respectively, with least physiological loss in weight and microbial count.
Sanitization using 30 ppm sodium hypochlorite solution for 10 minutes was equally effective as hot water dip at 50±20C, whereas ozonization was effective as hot water treatment in stage 2 pineapple alone.
Based on efficiency and economics in maintaining the extended shelf life with least PLW and microbial load, hot water dip at 50± 20C for one minute was selected as the best pre-treatment for both maturity stages and was selected for the second part of the experiment.
In the second part of the experiment, harvested pineapple fruits of two maturity stages were independently subjected to hot water dip at 50± 20C for one minute and stored under low (240C) and ambient (320C) temperature conditions along with untreated fruits and the stored fruits were subjected to evaluation of physiological, chemical and sensory quality parameters.
Untreated pineapple fruits of stage 1 maturity stored under ambient temperature had least shelf life (12 days), highest physiological loss in weight (12.29 %) and had to be discarded after 12 days due to spoilage. Fruits treated with hot water and stored under low temperature conditions had maximum shelf life (21.25 days), least PLW (4.53%), minimum TSS (14.26 °B), total sugar (10.45%) and reducing sugar (4.36%), highest acidity (0.91%), non-reducing sugar (6.09%) and vitamin C (22.85%) after 12 days of storage.
In case of fruits of stage 2 maturity, untreated pineapple fruits stored under ambient temperature had least shelf life (10.5 days) and highest physiological loss in weight (8.40%). Fruits treated with hot water and stored under low temperature had maximum shelf life (18.25 days), least PLW (2.48%), minimum TSS (15.78°B), total sugar (11.15%) and reducing sugar (4.13%), highest acidity (0.81%), non-reducing sugar (7.02%) and vitamin C (22.91%) after 9 days of storage.
All the treatments were effective in maintaining high sensory quality parameters viz., appearance, flavour, texture, taste, flesh colour and over all acceptability, of which hot water dip treatment followed by low temperature storage had the highest mean score while untreated fruits stored under ambient temperature recorded the lowest scores in both maturity stages.
In general, fruits treated with hot water when stored under low temperature conditions had better physiological and chemical quality parameters and the same were reflected in acceptability scores of the commodities. Hot water treatment alone gave better quality pineapple fruits compared to untreated ones, and a combination of hot water treatment and low temperature storage further improved the quality and shelf life of fruits of both maturity.
It can be concluded that pineapple fruits (var. Mauritius) harvested with crown and two cm stalk at stage1 maturity when subjected to hot water treatment at 50±20C for 1 minute followed by low temperature storage (240C) could extend the shelf life of pineapple meant for distant markets up to 21.25 days. Same management practice resulted in extension of shelf life to18.25 days for stage 2 maturity stage pineapple fruits meant for the local market.