Page 33 - FoodFocusThailand No.233 August 2025

SPECIAL FOCUS

in detached mature-green fruit, it is likely that red light influences the biosynthesis
of tomato carotenoids by enhancing the first step of carotenogenesis through
modulation of phytoene synthesis activity, which is an important regulatory step
in carotene biosynthesis (Panjai et al., 2021).
As health and environmental awareness have become mainstream among
consumers, the use of postharvest technology in combination with red light has
emerged as an environmentally friendly approach. This method is chemical-free
and meets the needs of modern consumers who seek safe food with maximum
nutritional value. It is particularly relevant to the minimally processed food sector
and the health food industry, both of which continue to show growth in the global
market (Kaushik et al., 2020; Tomay et al., 2019). As a result, the application of
appropriate light sources—such as LED or laser light within specific wavelengths—
has been adopted to extend the shelf life of produce, reduce postharvest losses,
and preserve nutritional quality, as well as maintain physical attributes such as
color, aroma, taste, and texture of agricultural products (Alzamora et al., 2021).
This technology aligns with the concept of functional food development and
health-oriented products, which are gaining increased attention from consumers—
รููปที่่� 1 มะเขืือเทศระยะสุุกขื้�นท่� 1 especially in international markets such as the European Union, the United States,
Figure 1 Tomatoes at ripening stage 1 and Japan, where strict regulations and standards regarding food safety and
ที่่�มา/Source: Garcia et al., 2019 environmental protection are enforced (Kaushik et al., 2020).
Research and development of postharvest light technology is expected to
continue advancing, with increasing integration of modern technologies such
‘Red light’ and the enhancement as nanotechnology, smart sensors, and artificial intelligence. These innovations
of ‘key compounds’ in enable real-time monitoring and control of environmental conditions and product
postharvest tomatoes quality, meeting the demands of the modern food industry, which emphasizes
Over the past few decades, there has safety, quality, and sustainability in all aspects (Alzamora et al., 2021).
been extensive research on increasing
the levels of lycopene, beta-carotene,
flavonoids, and phenolic compounds in
tomatoes after harvest. Among various More Information Service Info C003
approaches, the use of red light has
been identified as an effective method
to enhance the levels of these
compounds. As shown in Figure 1,
tomatoes harvested at the green stage
(ripening stage 1) were stored under
continuous red light (peak wavelength
at 665 nm), providing a Photosynthetic
Active Radiation (PAR) of 113 μmol m -2
per day, at 20 °C and 80% relative
humidity. The results revealed that
tomatoes exposed to red light showed
a higher accumulation of lycopene,
beta-carotene, flavonoids, and phenolic
compounds compared to those stored
in the dark under the same conditions.
Tomatoes treated with red light fully
ripened within 10 days after harvest—
faster than those kept in the dark (Panjai
et al., 2017). Moreover, further studies
also indicated that continuously
exposing green tomatoes to red light for
14 days stimulated the synthesis of
related bioactive compounds more
effectively than intermittent red light
exposure (e.g., 12 hours, 6 hours, or 30
minutes per day) (Panjai et al., 2019).
Additionally, the tomato tissues directly
exposed to red light contained higher
levels of these compounds compared
to deeper tissues that were not in direct
contact with the light. Due to the fact
that red light and its intensity had
a positive effect on carotenoid synthesis

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