Sutthiwal Setha

This study investigated the effects of high-pressure processing (HPP) at 400 and 600 MPa (10 min, 25 °C) compared with conventional thermal processing (CTP; 10 min, 80 °C) on the quality of “ Phulae ” pineapple purée ( Ananas comosus L. cv. Phulae).

BACKGROUND: High‐voltage electrostatic field (HVEF) is a physical postharvest handling technique, which is clean and safe technology for consumers and the environment and can be used to extend the postharvest shelf life of avocados. Therefore, the effects of a HVEF on cell wall modification related to mesocarp softening in avocados during storage were investigated, as well as physiological changes. Avocados were treated with 1 kV cm ⁻¹ for 120 min and then packed into carton boxes. Fruit without an HVEF served as the untreated control. The fruit were subsequently stored at room temperature (25 ± 2 °C) and 75 ± 5% relative humidity for 7 days. RESULTS: The results revealed that the HVEF had physiological affects by significantly delaying respiration rate and ethylene production. HVEF‐treated fruit maintained fruit firmness (15.34 N), representing a 3.5‐fold (approximately 352%) increase compared with control samples (3.39 N), and exhibited approximately 30% lower water‐soluble pectin (WSP) content (0.41 vs. 0.56 g L ⁻¹ ) at 3 days after treatment. These changes were correlated with a negative relationship between firmness and WSP content. Additionally, the HVEF treatment significantly repressed the activities of key cell wall‐degrading enzymes: pectin methyl esterase, polygalacturonase, and pectate lyase. Fourier transform infrared spectroscopy – a molecular analysis technique – and principal component analysis – a statistical method for data interpretation – confirmed structural changes in the pectin. Furthermore, compared with the untreated control treatment, HVEF significantly maintained peel color and delayed a decrease in hue° value. CONCLUSION: These results indicated that HVEF could be an effective method for extending avocado shelf life by approximately 2 days compared with the control, based on the delay in reaching the edible‐ripening stage (firmness < 10 N and hue° < 90°). Overall, HVEF treatment provides a non‐destructive and environmentally friendly approach to delay ripening and extend the postharvest shelf life of avocados under ambient conditions. © 2025 Society of Chemical Industry.

Background and Aims: Color, a key determinant of grape berry quality, is influenced by light, temperature, and plant hormones during development. We investigated the effects of red‐, blue‐, and combined red‐and‐blue‐light irradiations on photoreceptors, abscisic acid (ABA) signaling, and anthocyanin biosynthesis in order to clarify their mutual relationships. Methods and Results: The experiment was conducted over two consecutive years (2023–2024) using the same nine “Kyoho” grapevines, which were eight years old at the start of the study. In 2023, treatments consisted of irradiating grape clusters with either red‐light‐emitting diodes (LEDs) or blue LEDs. In 2024, the treatments were modified to irradiation with blue LEDs or a combination of red and blue LEDs. Compared to an untreated control group, the irradiation of grape clusters with red or blue LEDs at 240 μmol m ⁻² s ⁻¹ both significantly increased the expressions of the photoreceptor genes VvPHYa (phytochromes) , VvPHYb , VvCRYa (cryptochromes), and VvPHOT2 (phototropins), those of genes VvSnRK2.6 (an SNF 1‐related protein kinase) and VvABF2 (an ABA‐responsive element‐binding transcription factor) involved in the activation of ABA signaling, and those of genes VvMYBa1 and VvUFGT involved in anthocyanin synthesis, as well as anthocyanin synthesis. The expression of VvPP2C9 (protein phosphatase 2C9), which is negatively related to ABA signaling, was decreased. There were no significant differences in these factors between the red‐ and blue‐irradiated sections. The combined treatment with red and blue light, as well as blue‐light exposure alone, upregulated photoreceptor genes’ expression, ABA signaling, anthocyanin synthesis enzyme genes’ expression, and anthocyanin synthesis compared to the untreated control, whereas no difference was observed between the combined treatment and the blue‐light treatment. Conclusions: These results suggest that both red‐ and blue‐light exposure stimulate ABA signaling in grape skins and that the activation of either the red‐ or blue‐light receptors promotes anthocyanin synthesis.