Abstract:
Tomato (Solanum lycopersicum L.) is one of the higher-ranking commercial vegetable crops in
the World. This study was to investigate the effect of different colours such as blue, red, yellow,
green, and white light of LED lighting and dark condition (control) on postharvest quality and
microbial growth on harvested tomato fruits. Experiment was conducted in complete
Randomized Design in laboratory providing lighting with light intensity of 5555.5-8333.3 lux/m2
in 30 cm x 22 cm x 30 cm cardboard boxes with temperature range of 25 0C-28 0C and relative
humidity of 80%. Fruit quality parameters were studied such as fresh weight loss, pH, total
soluble solid (TSS), hardness, lycopene, total carotene, ascorbic acid and in vitro microbial
growth under different colours of LED light. At the 25th day of storage, fresh weight loss %
significantly high in blue LED light (11.08±1.141%) and the lowest value was recorded in
control (6.20±1.41%). At 9th day L* value significantly high under the control (58.01±1.849)than
other treatments. L* value significantly high under the white LED light in 17th (52.42±1.10) and
19th (49.08±1.7) days than others. a*and b* values of colour, hardness and pH were not
significantly varied under the LED lights and control throughout the storage. On 25th day the
highest TSS was recorded (4.50± 0.52%) in blue LED light whereas, the lowest TSS was recorded
in white (3.5±0.52%). The highest lycopene content was recorded in red LED light in 21th
(178.56±3.59 mg/kg) and 25th (237.35±22.8 mg/kg) days. The lowest Lycopene content
recorded in green LED light in 21th (65.373± 3.59 mg/kg) and 25th (90.53±22.8 mg/kg) days. At
21st day the highest carotene content was recorded in red LED light (0.3461±0.0047 mg/kg).
The lowest carotene content was recorded in green light treatment (0.1274±0.047 mg/kg). 1st
(0.177±0.048cm) and 2nd (0.333±0.074cm) days after inoculating the highest in vitro microbial
colony growth was recorded in control and there was no in vitro microbe colony growth in LED
light treatments in 1st and 2nd days. LED light colour mainly red, white, and blue considerably
effect on postharvest fruit quality of tomato such as fresh weight loss %, lycopene content, total
solid content (TSS), and total carotene. LED light spectrum effectively suppressed microbial
growth on fruit surface especially red light which evident by delaying of microbial growth in in
vitro microbial study.
