# Efficacy of Herbal Extracts-Based Nano-Formulations in Extending Guava Fruit Shelf-Life
## 4 Discussion  
The guava (_Psidium guajava_ L.) with chromosome number \(2n=22\) is a tree within the the _Mytraceae_ family. Commonly known as \"Apple of the Tropics\", it is grown in tropical and subtropical climatic regions. It is an evergreen, easily adaptable and resilient tree. Loss occurs due to improper storage of fruit and lack of packaging amenities. Fruits are imperative for good health as they provide macro and micronutrients to the body. Edible coatings are an effective method in reducing post-harvest losses. In guava, use of edible coatings such as xanthan gum, carnauba wax, 2% chitosan, carboxymethyl cellulose and cashew gum, cassava starch and cinnamon essential oil has been reported [21; 22; 23; 24]. In the  
Figure 8: Effect of nanoformulations on color change of guava fruits (Hisar Surkha) during storage at \(32\pm 2\) °C. Figure 7: Effect of nanoformulations on color change of guava fruits (Hisar Surkha) during storage at \(25\pm 2\) °C. present study, herbal extracts of ajwain (_Trachyspernum amnt_) seeds and giloy (_Tinosporia cordipholia_) leaves and stems were prepared. Addition of these extracts improves the coatings' efficiency. Similar results have been reported by [PERSON] and [PERSON] [25], where gum arabic: sodium caseinate: tulsi extract improved the shelf life of guava fruit to 7 days against control which had 4 days shelf life at 28 \({}^{\circ}\)C. Table 3 shows the effect of different edible coatings on shelf life of fruits. Synthesis of herbal nanoformulations (NFs) was carried out using alginate: CaCl\({}_{2}\) in combination with ajwain and giloy extracts using the ionotropic gelation method. Ion or ionotropic gelation, also known as polyelectrolyte gelation or complexation, is the most widely used method of nanoencapsulation synthesis using biocompatible and non-toxic polymers [29]. This gelation is the result of mixing of oppositely charged biopolymers at low concentration in solutions, which should be less than their gelling points. Alginate is produced by marine brown algae and is used in the synthesis of edible coatings and nanocapsules. The different sized insoluble nanoparticles of calcium alginate can be formed using soluble sodium alginate and calcium chloride at different concentrations. Particles of 100 nm to 2 mm have been synthesized using sodium alginate and CaCl\({}_{2}\) for drugs delivery [30]. The NFs exhibited good antioxidant and antimicrobial activity due to addition of herbal extracts. Ajwain and giloy extracts were reported as having antibacterial properties but at nanoscale these activities were further enhanced. This is due to nanoparticles' smaller size to volume ratio which provides a larger surface area for herbal extracts' bioactive compounds' interaction with the fruit surface. Herbal extracts are full of antioxidant content and thus, enhance fruit resistance against reactive oxygen species. All the synthesized nanoformulations are of nano size. Figure 5 shows the physiological loss in weight (PLW) of guava fruits during storage and the effect of T1, T2 and T3 nano-formulations (NFs) on fruit ripening. The maximum PLW was 17.21% and 15.57% in control fruits at 12 DAT and 10 DAT during storage at 25 \(\pm\) 2 \({}^{\circ}\)C and 32 \(\pm\) 2 \({}^{\circ}\)C, respectively. Minimum PLW was observed in T2 coated fruits, with 12.28% and 9.97% weight loss at 25 \(\pm\) 2 \({}^{\circ}\)C and 32 \(\pm\) 2 \({}^{\circ}\)C, respectively. PLW is the result of respiration and moisture evaporation between the fruit tissue and surrounding environment, and is affected by post-harvest treatments [31]. The loss in PLW of guava is due to loss of bound and free moisture through evapotranspiration and respiration. Higher moisture loss also impacts parameters such as firmness and color change [32]. [PERSON] and [PERSON] [33] reported improved shelf life till 12 th day for guava coated with flaxseed protein: guar gum: glycerol as compared to uncoated control guava