Experimental materials: litchi variety namely ‘Bombai’
Experimental treatments: 8 treatments & two factors.
Factor A: Temperature
T1: Ambient temperature
T2: 4ºC temperature
Factor B: PP bags (Polypropylene bag)
P1: Control (unwrapped)
P2: 50µ PP bag
P3: 75µ PP bag
P4: 100µ PP bag
Experimental design: The two factor experiment was laid out in completely randomized design with three replications. A total of 192 fruits of more or less similar shape and size and free of visible disease symptoms were used.
Parameter studied:
Total weight loss
4 fruits of each replication of each treatment were weighed by using an electric balance on the first day of storage and at every 2-day intervals.
Weight loss (%) = (IW-FW) x 100
Where,
IW = Initial weight of fruits (g)
FW = Final weight of fruits (g)
Moisture content
Moisture content (%) = (IW-FW)/ FW x 100
Where,
IW = Initial weight of pulp (g)
FW= Final weight of oven-dried pulp (g)
Total soluble solids; Total soluble solids (TSS) content of litchi pulp was estimated by using Abbe's Refractometer.
Pulp pH: Preparation of standard buffer solution pH -7 and pH-4 buffer tablet BDH (chemicals Ltd., Poole, England) was dissolved in water and made up to the mark of 100 ml with distilled water.
Extraction of fruit juice: For the determination of pulp pH, 5 g of fresh pulp was taken in a conical flask containing 10 ml of distilled water. Then the pulp was crushed thoroughly in a mortar and pestle and extract was filtered through two layers of cloths.
Procedure: The pH meter (Hannan) was standardized by using a buffer solution of pH -7 and pH-4 when correction for temperature was also taken into consideration. On completion of calibration, the electrode was washed twice with distilled water, rinsed with litchi juice and dipped into the juice. The pH was recorded.
Titratable acidity: Titratable acidity of litchi pulp was determined according to the method mentioned by Rangana (1979). The following reagents were used for the determination of titratable acidity.
- Standard NaOH solution (0.1N)
- 1% phenolphthalein solution
Disease incidence: Disease incidence refers to the percentage of fruits infected by disease organisms. The fruits were critically examined every day for the appearance of disease symptoms. The first count was made at the 3rd day of storage. The diseased fruits were identified symptomatically.
Shelf life: The shelf life of litchi fruits as influenced by different varieties was calculated by counting the days required to ripe fully as to retaining optimum marketing and eating qualities.
Statistical analysis: For the experiment, the collected data were statistically analyzed by the Analysis of Variance (ANOVA) test. The means of different parameters were compared by the least significant difference (LSD) as described by Gomez and Gomez (1984).