Recently, LEDs with various light qualities have been used in closed plant factories, and they are known to have different effects on the growth and quality of crops. Therefore, this study was conducted to investigate the change in growth and quality in mini red romaine lettuce using LEDs with various light qualities. Wide red spectrum (WRS)-LEDs, blue (B)-LEDs, blue + red (BR)-LEDs, red (R)-LEDs, and white (W)-LEDs were used as the artificial light sources. Regarding growth, the R-LED treatment showed the most positive effect, but the leaf shape was not normal and the Hunter b* value was not suitable because it was higher than that of the other treatments. The Hunter a*, SPAD, and NDVI values of the B- and BR-LED treatments were effective, but this was not the case for those of the R- and W-LED treatments. The anthocyanin reflectance index 1 (ARI1) was 20 times higher in the B-LED treatment than in the R-LED treatment, and the ascorbic acid content was the highest in the WRS-LED treatment. In the sensory evaluation, bitterness and sweetness showed opposite tendencies. Regarding the overall preference, the BR-LED treatment received the highest score. Correlation analysis showed that the bitterness was closely correlated with the anthocyanin content and leaf color. Taken together, BR-LEDs provided a good top fresh weight, dark red leaves, and high anthocyanin and ascorbic acid contents, with the highest overall preference; therefore, BR-LEDs were the most suitable for the cultivation of mini red romaine lettuce.

Water loss, interwoven with other factors, is identified as the cause of chilling injury to sweet peppers. The breaker stage is the most vulnerable of all maturity stages. The purpose of this study was to see if increasing the storage relative humidity (RH) reduces the chilling injury and to compare its effect on breaker-stage fruits to red-ripe fruits at a normal RH. The fruits were stored at 5 °C with a RH of 98 ± 2% and 70 ± 6% for high and low RH, respectively. After 15 days of cold storage, the fruits were moved to ambient conditions for 3–5 days for chilling injury symptoms to appear. The results showed that high RH storage reduced fruit water loss by 4–4.5% compared to low RH storage, resulting in fewer chilling injury symptoms regardless of fruit maturity stage. Due to the increased RH, cell membrane damage indicators such as electrolyte leakage, MDA, respiration, and ethylene production rates were shown to be reduced, while brix and color were well maintained, indicating reduced or stopped senescence. Furthermore, DPPH antioxidant activity and vitamin C were retained and optimized. The microbiological analyses also showed that a high RH may not promote the growth of microorganisms as quickly as may have been thought. Finally, the findings of this study indicate that breaker-stage peppers stored at a high RH may be less susceptible to chilling injury than red-ripe peppers stored at a low RH.

This study investigated the effects of supplemental inter-lighting on paprika (cv. Nagano RZ) in South Korea in summer using various LED light sources. The following LED inter-lighting treatments were used: QD-IL (blue + wide-red + far-red inter-lighting), CW-IL (cool-white inter-lighting), and B+R-IL (blue + red (1:2) inter-lighting). To investigate the effect of supplemental lighting on each canopy, top-lighting (CW-TL) was also used. Additionally, a control without supplemental lighting was included for comparison. Significant variations were observed in the plant growth indexes 42 days after treatment. The SPAD values and total chlorophyll content in the last period of cultivation were significantly higher than those of the control. In November, the marketable fruit yield was significantly higher than that of the control. QD-IL, CW-IL, and CW-TL resulted in significantly higher values of total soluble solids than the control, and CW-IL resulted in higher values of ascorbic acid content than the control. Regarding the economic analysis, CW-IL resulted in the highest net income rate (12.70%) compared with the control. Therefore, the light sources of CW-IL were assessed as suitable for supplemental lighting due to the highest total soluble solids, ascorbic acid content, and net income rate obtained.

Temperate fruits, mostly comprising pome, stone fruits, and berries with immense nutritional benefits and a storehouse of various therapeutic phytochemicals, are prone to several physiological disorders immediately after harvest. The etiology, symptom progression, and decay incidence are influenced by pre-harvest and post-harvest factors, causing significant economic loss with respect to both the energy and economics invested. Respiratory end products, ethylene generation, and enzymatic activities interact to influence the metabolic response and associated biochemical variation. Advanced packaging technologies have emerged as innovative solutions to curtail these post-harvest problems. The design and development of novel packaging technologies need to critically understand the respiratory behavior of the fruits and their associated metabolic functions. A desirable polymer or packaging technology should exhibit enhanced barriers to the gases while providing adequate support to the fruit matrix. In addition, it should also fulfill the role of environmental sustainability and the circular economy. The outcome of this review will highlight the importance of proper post-harvest procedure, appropriate pretreatment, packaging matrix selection, and the storage conditions for effective and enhanced shelf-life storage. Therefore, this review was structured in two phases; the first phase discusses the biochemical understanding of the fruit during storage and transit in response to stress factors. The next phase highlights the various packaging interventions (polymers, biodegradable films, edible coatings, smart packaging, nano-packaging) taken to address these issues, with a key focus on shelf-life enhancement. Further, the key limitations of each technology are appraised.

Light quality can be stated to be the identity of an artificial light source, and although the response of light quality may vary depending on the crop, the effect is clearly visible and can produce various results depending on the combination of an artificial light source. This study investigated the spectral reflectance, photosynthetic performance, and chlorophyll fluorescence of mini green romaine lettuce based on light quality. Most parameters related to spectral reflectance showed the best results under blue light, and photosynthetic performance was more effective with mixed light than with single-colored light, among which blue + red (BR)-LED was the most suitable. Red light was ineffective, showing mostly low results in parameters of spectral reflectance and photosynthetic performance. In the case of chlorophyll fluorescence, the light quality influenced photomorphogenesis, resulting in increased leaf length and width with R- and quantum dot (QD)-LED, which expanded the leaf area and allowed for more external light to be captured (ABS/RC and TRo/RC). However, the ratio of electronized energy (ETo/RC) was low, and the amount of energy dissipated as heat (DIo/RC) was high. Consequently, the degree of electron acceptor reduction and overall photosynthetic performance (PI_ABS and PI_total) were lower compared to other light qualities. Additionally, the contrasting results of QD-LED and BR-LED were attributed to the form of red light and the presence or absence of far-red light when comparing spectra. Principal component analysis also clearly distinguished light qualities for photosynthesis and growth. Growth was increased by red (R)- and QD-LED, while photosynthetic performance was increased by BR- and blue (B)-LED.

The effect of 10% CO₂ pre-storage treatment for 12, 24, and 48 h alongside modified atmosphere packaging (MAP) on chilling injury was determined in this study. This study found significant interactions between chilling injuries and cell membrane damage indicators. The results show that chilling injuries can be somewhat reduced by the use of CO₂ treatment for sweet peppers. It was noticed that the fruit’s respiration rate increased as the treatment duration increased immediately after the treatments, while the resultant did not affect the ethylene production rate, electrolyte leakage, or malondialdehyde. Similarly, after cold storage and on the final day, no really significant differences were shown in all those parameters except for the weight loss rate, chilling injury, calyx browning, and firmness, which were at the poorest state in the control group. Of all the treatments in this study, MAP appeared to be the best treatment, and preference may be given to the 24 h treatment of pretreated fruits. Weight loss, firmness, calyx browning, and chilling injury were maintained best in MAP due to the presence of CO₂ and high humidity.