Sprout Suppressants in Potato Storage: Conventional Options and Promising Essential Oils—A Review

Exploring hydrodynamic cavitation for citrus waste valorisation in Malta: from beverage enhancement to potato sprouting suppression and water remediation

Introduction: The endorsement of circular economy, zero-waste, and sustainable development by the EU and UN has promoted non-thermal technologies in agro-food and health industries. While northern European countries rapidly integrate these technologies, their implementation in Mediterranean food-supply chains remains uncertain. Aims: We evaluated the usefulness of hydrodynamic cavitation (HC) for valorizing orange peel waste in the fresh orange juice supply chain of the Maltese Islands. Method: We assessed: a) the effectiveness of HC in extracting bioactive compounds from orange peels (Citrus sinensis) in water (35°C) and 70% (v/v) ethanol (-10°C) over time, compared to conventional maceration, and b) the potato sprouting-suppression and biosorbent potential of the processed peel for copper, nitrate, and nitrite binding. Results: Prolonged HC-assisted extractions in water (high cavitation numbers), damaged and/or oxidized bioactive compounds, with flavonoids and ascorbic acid being more sensitive, whereas cold ethanolic extractions preserved the compounds involved in radical scavenging. HC-processing adequately modified the peel, enabling its use as a potato suppressant and biosorbent for copper, nitrate, and nitrite. Conclusion: Coupling HC-assisted bioactive compound extractions with using leftover peel for potato-sprouting prevention and as biosorbent for water pollutant removal offers a straightforward approach to promoting circular economic practices and sustainable agriculture in Malta.

Impact of the Temperature Reconditioning of Cold-Stored Potatoes on the Color of Potato Chips and French Fries

The effect of temperature reconditioning on cold-stored potato tubers was investigated for three popularly consumed potato varieties (Shangi, Unica, and Dutch robjin) grown in Kenya. The potatoes were stored at 4 °C for 30 days, followed by removal and storage at 22 ± 3 °C for 9 days during which changes in sugar concentration were evaluated every two days. In parallel, potato chips and French fries were processed, and their colors were determined. The results showed that sugar content decreased significantly with increasing reconditioning time. The relative decrease in fructose content was the highest (p < 0.05) in Dutch robjin (57.49%), followed by Shangi (49.22%) and Unica (38.18%). Glucose content decreased by 54.1% in Dutch robjin, 49.5% in Shangi, and 50.8% in Unica. The lightness (L*) of French fries and chips increased significantly (p < 0.05) with reconditioning time while the redness (a*) values decreased significantly (p < 0.05) across all varieties. The correlation between lightness and the total reducing sugar content of the potatoes was r < -0.93, indicating a strong negative correlation for both products. The coefficient of determination showed that the glucose content of the tubers accounted for 80.5-97.6% of the lightness of French fries and 88.4-94.2% for potato chips. The critical glucose content range for acceptable products in French fries and chips based on the color (L* and a*) values was 12-22 mg/100g and 8-14 mg/100g, respectively, for the varieties in this study.

Harnessing Plant's Arsenal: Essential Oils as Promising Tools for Sustainable Management of Potato Late Blight Disease Caused by Phytophthora infestans-A Comprehensive Review

Potato late blight disease is caused by the oomycete Phytophthora infestans and is listed as one of the most severe phytopathologies on Earth. The current environmental issues require new methods of pest management. For that reason, plant secondary metabolites and, in particular, essential oils (EOs) have demonstrated promising potential as pesticide alternatives. This review presents the up-to-date work accomplished using EOs against P. infestans at various experimental scales, from in vitro to in vivo. Additionally, some cellular mechanisms of action on Phytophthora spp., especially towards cell membranes, are also presented for a better understanding of anti-oomycete activities. Finally, some challenges and constraints encountered for the development of EOs-based biopesticides are highlighted.

Melissa officinalis L. as a Sprout Suppressor in Solanum tuberosum L. and an Alternative to Synthetic Pesticides

The goal of this research was to screen plant essential oils (EOs) as sprout inhibitors or suppressors in potato (Solanum tuberosum L.). Three controlled environment experiments were conducted to screen 18 EOs and several pure compounds as sprout inhibitors. The EOs were applied using the wicked method on potato cv. Gala in 19 L plastic containers. The results indicated that Melissa officinalis L. EO inhibited sprouting, while Coriandrum sativum L. seed oil and the EO blend of Lavandula angustifolia Mill. and Salvia sclarea L. suppressed sprouting. The EOs of interest were analyzed using gas chromatography coupled to mass spectrometry (GC-MS) and/or a flame ionization detector (GC-FID); the detailed chemical profiles are provided. The M. officinalis EO was fractionated into seven fractions, and these were tested on minitubers. We identified two fractions (F and A) that suppressed potato sprouting better than the whole oil. The GC-MS-FID analyses of M. officinalis EO fraction A identified myrcene, Z-ocimene, E-ocimene, trans-caryophyllene, and α-humulene as the main constituents, while the main constituents of fraction F were α-terpineol, β-citronellol, and geraniol. The pure isolated compounds, together with the major compound in M. officinalis EO (citral), were tested for sprout suppression on three potato cultivars (Ranger Russet, Terra Rosa, and Dakota TrailBlazer), which revealed that β-citronellol reduced the sprout length and the number of sprouts in all three cultivars, while citral and (+)-α-terpineol reduced the sprout length and the number of sprouts in Ranger Russet relative to the two controls in all three cultivars. Myrcene had a stimulating effect on the number of sprouts in Cv. Terra Rosa. However, none of the pure compounds suppressed sprouting completely or were comparable to the EO of M. officinalis.