Aman Ullah Malik

Potato is the main source of income for the growers of middle Punjab, Pakistan. Despite being a key cash crop, potato yields remain below potential, mainly due to inefficient fertilizer management in alkaline sandy loam soils, necessitating strategies that can enhance tuber yields. This 2‐year study aimed to enhance potato yield by optimizing fertilizer application strategies, comparing conventional synthetic phosphorus (P) and nitrogen (N) applications with plant growth–promoting bacteria (PGPB)–coated biofertilizers. Potato cv. Sante was evaluated under three treatments: four split applications of synthetic P:N (185:250 kg ha ⁻¹ , control) fertilizer, six split applications of synthetic P:N (185:250 kg ha ⁻¹ ) fertilizer, and six split applications of PGPB‐coated P:N (185:250 kg ha ⁻¹ ) biofertilizer. Results showed that increasing the number of split applications improved all growth attributes. The highest performance was recorded with PGPB‐coated biofertilizers, which enhanced intercellular CO ₂ concentration by 91.6%, photosynthetic rate by 8.9%, and water use efficiency by 37.4% to the control, while reducing stomatal conductance and transpiration rate by 15.5% and 20.6%, respectively. Although photosynthetic rate correlated weakly with total yield, it showed a moderate relationship with rashan‐grade yield. Overall, PGPB‐coated P:N (185:250 kg ha ⁻¹ ) biofertilizers applied in six splits significantly improved total and rashan‐grade yields while minimizing downgrade yield. These findings support the use of PGPB‐coated biofertilizers as an eco‐friendly and efficient strategy for boosting potato productivity.

Fruits and vegetables are the pivotal sources of essential elements (vitamins and minerals), whose deficiency may cause different kinds of health issues; however, due to non‐judicious use of pesticides and unhygienic practices in the supply chain, fresh produce gets contaminated. These contaminants could be minimized by cooking, blanching, and chlorination at household level, but these thermal and chemical processing techniques negatively affect the product quality and nutrition value. When F & V is consumed in the raw form then these contaminants directly affect human health, which may lead to death or different syndromes. It is hard to eliminate these lethal contaminants from supply chain. Different decontamination technologies previously practiced at household level but have negative impacts on commodities' nutritional value and human health. Henceforth, some green techniques like ozonation, sonication, and ozosonication (O₃/US) are considered as emerging sanitizing technologies, without adversely affecting quality of horticultural commodities and human health, when used at optimum limit.

Post-harvest loss is a serious issue to address challenge of food security. A solar-grid hybrid cold storage system was developed and designed for on-farm preservation of perishables. Computational Fluid Dynamic analysis was performed to assess airflow and temperature distribution inside the cold chamber. The system comprises a 21.84 m³ cubical cold storage unit with storage capacity of 2 tonnes. A hybrid solar system comprising 4.5 kWp PV system, 5 kW hybrid inverter, and 600 Ah battery bank was used to power the entire system. A vapor-compression refrigeration system (2 tonnes) was employed coupled with three cooling pads (filled with brine solution) as thermal backup to store cooling (−4 °C to 4 °C). Potatoes were stored at 8 °C for a period of three months (May 2019 to July 2019) and the system was tested on grid utility, solar, and hybrid modes. Solar irradiation was recorded in range of 5.0–6.0 kWh/(m² × d) and average power peak was found to be 4.0 kW. Variable frequency drive was installed with compressor to eliminate the torque load and it resulted about 9.3 A AC current used by the system with 4.6 average Coefficient of Performance of refrigeration unit. The average energy consumed by system was found to be 15 kWh with a share of 4.3 kWh from grid and 10.5 kWh from solar, translating to 30% of power consumption from grid and 70% from solar PV modules. Overall, cold storage unit efficiently controlled total weight loss (7.64%) and preserved quality attributes (3.6 ⁰Brix Total soluble solids, 0.83% Titratable acidity, 6.32 PH) of the product during storage time.

Grafting has been reported as a factor regulating the metabolome of a plant. Therefore, a comprehensive metabolic profile and comparative analysis of metabolites were conducted from fully mature fruit of pumpkin-grafted watermelon (PGW) and a self-rooted watermelon (SRW). Widely targeted LC-ESI-MS/MS metabolomics approach facilitated the simultaneous identification and quantification of 339 metabolites across PGW and SRW. Regardless of grafting, delta-aminolevulinic acid hydrochloride, sucrose, mannose-6-phosphate (carbohydrates), homocystine, 2-phenylglycine, s-adenosyl-L-homocysteine (amino acids and derivatives), malic, azelaic, H-butanoic acid ethyl ester-hexoside isomer 1, (organic acids), MAG (18:3) isomer1, LysoPC 16:0, LysoPC 18:2 2n isomer (lipids) p-coumaric acid, piperidine, and salicylic acid-o-glycoside (secondary metabolites) were among the dominant metabolite. Dulcitol, mono-, and disaccharide sugars were higher in PGW, while polysaccharides showed complex behavior. In PGW, most aromatic and nitrogen-rich amino acids accumulated greater than 1.5- and 1-fold, respectively. Intermediates of the tricarboxylic acid cycle (TCA), stress-related metabolites, vitamin B5, and several flavonoids were significantly more abundant in PGW. Most lipids were also significantly higher in grafted watermelon. This is the first report providing a comprehensive picture of watermelon metabolic profile and changes induced by grafting. Hence, the untargeted high-throughput LC-ESI-MS/MS metabolomics approach could be suitable to provide significant differences in metabolite contents between grafted and ungrafted plants.

The effect of Aloe vera (ALV) coating was studied on chillies at 10 ± 1°C for 28 days. ALV gel‐coated chillies showed reduced weight loss, disease incidence, red chili percentage, respiration rate, electrolyte leakage, hydrogen peroxide, and superoxide anion contents. The ALV coating maintained general acceptance in terms of visual quality and marketability index with higher chlorophyll contents, ascorbic acid contents, total phenolic contents, and total antioxidants. In addition, ascorbate peroxidase, catalase, superoxide dismutase, and peroxidase activities were markedly higher in coated chillies compared to control. The biochemical attributes such as soluble solids content, acidity, sugar: acid ratio, and juice pH were non‐significantly affected by ALV application; however, the said attributes were comparatively higher in contrast to control. In conclusion, ALV edible coating could be used as an eco‐friendly approach for delaying senescence and maintaining the postharvest quality of green chillies up to 28 days. Practical applications Green chilies being highly perishable exhibit limited postharvest life with rapid loss of water, shrivelling, wilting, disease incidence, and reduced consumer acceptability. ALV gel coating significantly delayed postharvest senescence, reduced disease spread, maintained higher antioxidant activities of green chilies during cold storage. Therefore, ALV coating [50%] would be the suitable alternative to synthetic preservatives for extending the storage life and conserving the quality of green chilies.

Aloe vera (ALV) with its unique nutritional profile is being used for food, health, and nutraceutical industries globally. Due to its organic nature, ALV gel coating has created lot of interest for exploring its potential in extending the shelf and storage life of fresh produce. ALV gel coating plays imperative role in delaying fruit ripening by lowering ethylene biosynthesis, respiration rate, and internal metabolic activities associated with fruit softening, color development, enzymatic browning, and decay. ALV gel coating reduces the microbial spoilage due to its antifungal properties and maintains visual appearance, firmness, sugar: acid ratio, total antioxidants, and phenolic contents with conserved eating quality. ALV coated fruits and vegetables showed reduced weight loss, superoxide ion (), hydrogen peroxide (H₂O₂), ion leakage, and soluble solids content and exhibited higher acidity, anthocyanins, ascorbic acid, catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) activities. It also delayed the enzymatic browning by inducing peroxidase (POD) activity during storage. Recent local studies also revealed that ALV gel coating markedly conserved higher consuming quality and extended storage period (>1.34‐fold) of different fruits and vegetables. Overall, Aloe vera gel coating alone or in combination with other organic compounds has shown great potential as a food‐safe and eco‐friendly coating for maintaining the quality of fruits and vegetables over extended period and reducing postharvest losses in the supply chain. Practical applications ALV gel is a plant‐based natural coating of eco‐friendly nature. The present review summarizes the updated information of ALV gel coating application, methods of extraction, combinations with other postharvest coatings, and its impact on quality of various fruits and vegetables. It also provides future insights for the development of commercially applicable ALV gel coating protocols through simulation studies. So, being a natural coating, ALV gel has tremendous potential to be used in fruit and vegetable industries around the globe.

Samar Bahisht Chaunsa’ and ‘Sufaid Chaunsa’ are highly admired commercial mango cultivars of Pakistan in domestic and international markets. Fruit fly being a quarantine pest has become a significant barrier in mango export trade and needs specific postharvest disinfestation treatment before export to certain countries. Presently, postharvest vapour heat treatment (VHT) of mangoes at a certified facility is mandatory for export to Japan, however its impact on fruit quality have not been investigated. Hence, in two separate experiments, effect of quarantine VHT (Japanese protocol; 47°C for 25 min) was evaluated on the quality of two commercial mango cultivars. After VHT, treated and non-treated (control) fruits were kept at ambient conditions (26±3°C and 50-60% RH) till ripening. At eating ripe stage, VHT-treated ‘Samar Bahisht Chaunsa’ mango fruits exhibited significant reduction in postharvest disease incidence and showed higher concentrations of total phenolic contents, total antioxidants, carotenoids with better eating quality (taste, flavour, texture, aroma and pulp colour) as compared to untreated control fruit. ‘Samar Bahisht Chaunsa’ mango fruits showed non-significant results for physiochemical attributes such as peel colour, softness, total soluble solids (TSS), titratable acidity (TA), TSS:TA ratio and vitamin C, while more shriveling percentage was observed in non-VHT fruits. In second experiment, VHT treated ‘Sufaid Chaunsa’ fruits exhibited higher scores for peel colour, softness and total antioxidants, and reduced disease incidence and shriveling percentage with retained eating quality (taste). Non-significant results were observed for lenticel development, TSS, TA, TSS:TA ratio and phytochemicals (vitamin C, total phenolics, antioxidants and carotenoids) respectively. In conclusion, in both cultivars, VHT-treated fruits showed better ripening and organoleptic characteristics along with lower disease severity as compared to control. Thus, vapour heat treatment can be employed as safe quarantine measure for mango fruit export to Japan. Keywords: Vapour heat treatment; Japanese protocol; Disease incidence; Phenolics; Eating quality