The experiment was conducted at the field and laboratory of Postharvest Technology Section, Horticulture Research Centre, Bangladesh Agricultural Research Institute, Gazipur during January 2017. BARI Palong shak 1 was selected for the study. Seeds were collected from Olericulture division, HRC, BARI and grown in the research field of Postharvest Technology Section, HRC, BARI. To fulfill the experiment purpose, seeds were sown at different dates (every five days interval) to get the crop at a time.
The treatments were as follows: Factor A: Days after sowing. T1= 20 DAS. T4= 35 DAS. T2= 25 DAS. T5= 40 DAS. T3= 30 DAS. T6= 45 DAS.
Factor B: Packaging technique: P1= 1% perforated polyethylene, P3= newspaper wrap , P2= non-perforated polyethylene, P4= control
The design of the experiment was RCRD at field and CRD at the laboratory with three replications.
Preparation of spinach: The whole plant was collected from the field. Roots were washed with normal clean water and removed. Spinach plants were then packed in different packaging material and stored at ambient temperature. Some plants were used for collecting data from the fresh plants. Color of spinach: The color of spinach was measured with Chroma Meter (model CR-400/410). Five leaves of spinach per replication were evaluated from each treatment. Biochemical traits: Data on bio-chemical traits were determined on the initial day of harvest. The total acidity (%) and vitamin C (mg/100g) were determined according to AOAC (1994). Chlorophyll estimation: Leaves of each genotype were properly cut into small pieces and weighed 0.5 g and were taken for chlorophyll estimation. Chlorophyll a and chlorophyll b were estimated following Arnon’s method (Arnon, 1949). The absorbance of the solution was read at 645 and 663 nm for Chlorophyll a and Chlorophyll b.
Calculation:
Chlorophyll a (mg g-1) = {12.7 (D663) - 2.69 (D645)} × V/( 1000 × w)
Chlorophyll b (mg g-1) = {22.9 (D645) - 4.68 (D663)} × V/( 1000 × w)
Where, D = optical density
V = final volume of 80% acetone (ml)
w = dry weight of sample taken (g)
Dry matter estimation: 100 g of fresh spinach was weighed and dried at 700C temperature for seventy two hours and then kept in desecrator for cooling. After cooling it was weighed and the value was the dry matter percentage of spinach.
Sensory evaluation: Fifteen panelists were selected for sensory evaluation. The panelists were directed, prior to the test, to the actual descriptive levels used to evaluate the color, flavor, freshness, marketability, consumer preference, total acceptance and cooking performance of the spinach. The acceptability was evaluated based on a 9-point Hedonic scale. The higher the point was, the better the overall sensory quality was (9=like extremely, 8=like very much, 7=like moderate, 6=like slightly, 5= neither like nor dislike, 4=dislike slightly, 3=dislike moderate, 2=dislike very much, 1=dislike extremely).
Statistical analysis: Analysis of variance was done by one way ANOVA procedures of MSTAT-C software (Statistical package developed by the Crop and Soil Sciences Department of Michigan State University, USA). Comparisons among the samples were done by Duncan’s Multiple Range Test (DMRT).