Student research & Book chapter

Derived from tryptophan, melatonin (MT; N-acetyl-5-methoxytryptamine) is a ubiquitous indoleamine that is widely distributed in species ranging from microorganisms to mammals. It has been associated to play vital roles in the human body like cardiac rhythms, immunological enhancement, and antioxidant activity. In plants, it is a pleiotropic molecule with multiple roles, as it not only performs extensive functions like delaying senescence, growth and development regulation, exerting antioxidant effects, and facilitating adaption of plants to certain biotic and abiotic stress responses but also provides resistance to chilling injury and disease development. This paper reviews the latest progress in the multiple roles of MT in fruits, summarizes the pathways for its biosynthesis, and presents the relation of MT with plant hormones, like auxin, cytokinin, ethylene, gibberellins, abscisic acid, jasmonic, and salicylic acid, and highlights the effect of postharvest application of MT on physiology and quality of fruits, action mechanisms, and safety regulations of MT. Recent trends focus on using alternatives that are safe for postharvest produce and do not have major side effects. MT is a better alternative to hazardous chemicals being commercially used in the postharvest management of fruits and providing future directions for its utilization.

A study was conducted during 2008-09 to understand the effect of thinning, bending and spray of micronutrients on rejuvenated guava (Psidium guajava) cv. Sardar. 50% thinning of the shoots (C3) was superior to the rest of cultural practices and control in respect to growth, i.e., diameter of the shoot (11.40 mm), canopy volume (370.39 m3), relative growth of shoot at 75th, 105th and 135th days (41.90, 34.23 and 14.25% respectively), fruit yield (13.28 kg/plant), lowest number of the seeds (163.22), TSS (14%), total sugars (7.46%) and vitamin C content (238.33 mg/100 g pulp). Similarly, double spray of Zn (0.5%) + B (0.2%) + Mn (0.1%) in the month of August and October (S2) also significantly increased diameter of one-year-old shoot (9.13 mm), canopy volume (321.15 m3), relative growth of the shoot at 105th and 135th days (28.00% and 10.78%, respectively), fruit yield (12.63 kg/plant) and quality (TSS 13.20%, total sugars 6.98% and vitamin C content 239 mg/100 g pulp) over single spray and control. The interaction of cultural practices and spray of micronutrients were found to be superior over individual effect in rejuvenated guava. However, among all the interaction treatments maximum relative growth rate of the shoot at 135th days (13.98%), fruit retention (71.50%), fruit length (5.13 cm), fruit width (5.09 cm), fruit yield (14.02 kg/plant), size of seed cavity (2.53 cm) and minimum fruit drop (28.51%) and acidity (0.45%) were recorded in 50% thinning + double spray of Zn (0.5%) + B (0.2%) + Mn (0.1%) in the month of August and October (C3S2).

A study was conducted on guava cv. Lalit to find out the effect of irrigation and fertigation scheduling on WUE, FUE, moisture distribution pattern, leaf NPK content and nutrient uptake under intensive orcharding. The experiment consisted of 15 treatments combination comprising three different level of irrigation [50% (I1), 75% (I2) and 100% (I3) irrigation of pan evaporation] and five level of fertigation [20%(F1), 40% (F2), 60% (F3), 80% (F4) and 100% (F5) of recommended dose of NPK. Among the different treatment combination, maximum WUE (1038.50 kg ha-1 cm-1) was recorded under I1F4 treatment combination. Whereas, I3F5 resulted in maximum P content in leaves (0.28%), however, maximum yield plant-1 (6.75 kg), estimated yield ha-1 (33.75 t), uptake of N (652.92 kg ha-1), P (86.15 kg ha-1) and K (425.08kg ha-1) were obtained under I2F4. Treatment combination I2F3 obtained a maximum net return (Rs. 2,79,081.08) which was statistically at par with I2F4. Further, maximum B: C ratio (2.64) jointly recorded in I1F1 and I2F1, followed by (2.62) in I3F1. Treatments combination I2F3 and I2F4 were non significant between each other with respect to WUE, NPK uptake, yield tree-1 and estimated yield ha-1. Thus, based on the results of experiment we can conclude that treatment combination I2F3 (75 % irrigation of PE + 60% of recommended dose of NPK) efficiently utilized water and fertilizers in form of yield in guava cv. Lalit under intensive orcharding system.

A study was conducted to find out the effect of irrigation and fertigation scheduling on growth, flowering, yield and cost economics of guava cv. Lalit elanted under ultra high density planting system. The experiment consisted of 15 treatments combination comprising three different levels of irrigation [50 % (I1), 75% (I2) and 100% (I3) irrigation of pan evaporation] and five level of fertigation [20% (F1), 40% (F2), 60% (F3), 80% (F4) and 100% (F5) or recommended of NPK. Among the different treatment combination, highest shoot gain after pruning (39.90 cm), plant spread N-S (1.72 m), increase in girth of primary branch (0.315 cm) and canopy volume (1.265 m³) were recorded under I3 F5 treatment combination. Whereas, highest flowers shoot⁻¹ (47.60), fruit weight (96.91 g), pulp weight (70.84 g), pulp: seed ratio (14.96), number of fruits plant⁻¹ (77.70) and yield (6.75 kg plant⁻¹ & 33.75 t ha⁻¹) were recorded in I2 F4 treatment combination. However, treatment combinations I2 F4 and I2 F3 were found statistically at par with each other in respect of fruit weight, number of fruit plant⁻¹ and yield with each other in all the above parameters. Treatment combination I2 F3 gave the maximum net return (Rs. 2,79,081) per ha under ultra high density planting.

Abstract In the present research, wheat flour was replaced with onion skin powder (OSP) in 2%, 3.5%, and 5% concentration along with control to produce different pizza base variants. Prepared pizza doughs and base were investigated for different quality parameters. Rheology revealed that increased concentration of OSP elevated the storage modulus (G’) (solid nature) of pizza doughs. Colour measurement of both the doughs and pizza base exhibited lightness in control (L* 86.46 ± 0.39) and darkness in 5% OSP variant (L* 46.43 ± 0.69). Physicochemical investigation showed no significant difference however, a gradual increase was obtained in fiber, water, and oil holding capacity of pizza base. Texture properties showed that the addition of OSP imparted an increased trend of hardness i.e. 5% OSP variant had maximum hardness (14.87 ± 0.20 N). A higher level of total phenols, total flavonoids, and antioxidant activity was obtained in fortified products, which exhibits onion skin as a natural source of antioxidants for functional foods. Sensory evaluation revealed OSP 2% as the most accepted variant in terms of overall acceptability. The storage study of the pizza base revealed that controlled environment was the best-suited atmosphere for a longer shelf-life of pizza base.

Carotenoids and their metabolites play crucial roles in human health such as in immunity, cell differentiation, embryonic development, maintenance of plasma membrane integrity, and gastrointestinal functions, in addition to counteracting night blindness and other eye-related diseases. However, carotenoid bioavailability is highly variable and often low. The bioavailability of β-carotene, among the most frequently consumed carotenoid from the diet, is determined by food matrix related factors such as carotenoid dose, its location in food the matrix, the physical state in food, the presence of other food compounds in the matrix such as dietary fiber, dietary lipids, other micronutrients present such as minerals, and food processing, influencing also the size of food particles, and the presence of absorption inhibitors (fat replacers and anti-obesity drugs) or enhancers (nano-/micro-formulations). However, also host-related factors such as physiochemical interactions by gastrointestinal secretions (enzyme and salts) and other host-related factors such as surgery, age, disease, obesity, and genetic variations have shown to play a role. This review contributes to the knowledge regarding factors affecting the bioavailability of β-carotene (food and host-relegated), as well as highlights in vitro models employed to evaluate β-carotene bioavailability aspects.

Onion waste disposal issue could be solved by using onion skin as food ingredient. Therefore, the aim of present study is the estimation of flavonoid concentration, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities of onion skin of fifteen Indian cultivars. Flavonoid quantification was achieved by high performance liquid chromatography, which showed highest concentration of quercetin, quercetin 3-β-D-glucoside, luteolin and kaempferol in cv. ‘NHRDF Red’ (11,885.025 mg/kg), ‘Hissar-2’ (1432.875 mg/kg), ‘Pusa Riddhi’ (1669.925 mg/kg) and ‘Bhima Shakti’ (709.975 mg/kg), respectively in dry weight. Highest TPC and TFC were found in cv. ‘NHRDF Red’ while lowest were measured in cv. ‘Bhima Shubhra’. DPPH assay (%), ABTS assay (%) and FRAP assay (µmol gallic acid/g) were showed maximum antioxidant capacity for cv. ‘NHRDF Red’ whereas least obtained for cv. ‘Bhima Shubhra’. Skin of cv. ‘Hissar-2’ and ‘NHRDF Red’ are the best source of flavonoids and natural antioxidants.

Fruits and vegetables are the most utilized commodities among all horticultural crops. They are consumed raw, minimally processed, as well as processed, due to their nutrients and health‐promoting compounds. With the growing population and changing diet habits, the production and processing of horticultural crops, especially fruits and vegetables, have increased very significantly to fulfill the increasing demands. Significant losses and waste in the fresh and processing industries are becoming a serious nutritional, economical, and environmental problem. For example, the United Nations Food and Agriculture Organization (FAO) has estimated that losses and waste in fruits and vegetables are the highest among all types of foods, and may reach up to 60%. The processing operations of fruits and vegetables produce significant wastes of by‐products, which constitute about 25% to 30% of a whole commodity group. The waste is composed mainly of seed, skin, rind, and pomace, containing good sources of potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others. These phytochemicals can be utilized in different industries including the food industry, for the development of functional or enriched foods, the health industry for medicines and pharmaceuticals, and the textile industry, among others. The use of waste for the production of various crucial bioactive components is an important step toward sustainable development. This review describes the types and nature of the waste that originates from fruits and vegetables, the bioactive components in the waste, their extraction techniques, and the potential utilization of the obtained bioactive compounds.