Guava (Psidium guajava L.) Leaves: Nutritional Composition, Phytochemical Profile, and Health-Promoting Bioactivities.

Psidium guajava (L.) belongs to the Myrtaceae family and it is an important fruit in tropical areas like India, Indonesia, Pakistan, Bangladesh, and South America. The leaves of the guava plant have been studied for their health benefits which are attributed to their plethora of phytochemicals, such as quercetin, avicularin, apigenin, guaijaverin, kaempferol, hyperin, myricetin, gallic acid, catechin, epicatechin, chlorogenic acid, epigallocatechin gallate, and caffeic acid. Extracts from guava leaves (GLs) have been studied for their biological activities, including anticancer, antidiabetic, antioxidant, antidiarrheal, antimicrobial, lipid-lowering, and hepatoprotection activities. In the present review, we comprehensively present the nutritional profile and phytochemical profile of GLs. Further, various bioactivities of the GL extracts are also discussed critically. Considering the phytochemical profile and beneficial effects of GLs, they can potentially be used as an ingredient in the development of functional foods and pharmaceuticals. More detailed clinical trials need to be conducted to establish the efficacy of the GL extracts.

Enhancing the functionality of chitosan- and alginate-based active edible coatings/films for the preservation of fruits and vegetables: A review.

A number of studies have established the potential of chitosan and alginate-based edible film/coatings for preserving the quality attributes of fruits and vegetables. Findings demonstrate that these films/coatings act as a barrier on the surface of fruits and vegetables which causes higher moisture and water retention, create favourable micro-environments by optimizing the concentration of gases and delays ripening. Sincere efforts are being further made to improve the efficiency of edible films using functional additives such as phenolics, essential oils (EOs) and nano-forms. These additives have unlocked a new dimension for enhancing functional properties of alginate/chitosan-based films. These functional compounds are now emerging as an important component of edible films/coatings for prolonging shelf-life of fruits and vegetables. The present review comprehensively elaborates recent studies on functional additives and their mechanism of action. Here we also establish their proficiency in extending quality and shelf-life of various fruits including guava, pear, blueberries and vegetables like cucumber, capsicum and mushroom. Principles behind antimicrobial and antioxidant activities of additives in preventing the food spoilage are also reviewed. Competency of phenolics, EOs and nano-forms in extending the shelf-life without affecting the nutritional properties and safety aspects of the fruits and vegetables still require further attention.

Effect of chitosan and alginate based coatings enriched with pomegranate peel extract to extend the postharvest quality of guava (Psidium guajava L.).

The influence of chitosan (1% w/v) and alginate (2% w/v) coatings in combination with pomegranate peel extract (PPE; 1% w/v) on quality of guavas (cv Allahabad safeda) were studied. Restricted changes were recorded in respiration rate, ripening index, and instrumental colour values in case of the coated samples as compared to the control for 20days at 10°C. Samples coated with chitosan enriched with PPE (CHE) proved to be the most effective treatment in maintaining the overall fruit quality. Ascorbic acid, total phenolics, total flavonoids contents and antioxidant activity were recorded with restricted losses of 29%, 8%, 12%, 12% (DPPH) and 9% (FRAP), respectively for CHE samples at the end of storage. A higher degree of correlation (r>0.918) was established between various phytochemicals and AOA. PPE enriched coatings was proved efficient in maintaining the quality of guavas during 20days of low temperature storage.