Effect of chitosan-based coatings enriched with savory and/or tarragon essential oils on postharvest maintenance of kumquat (Fortunella sp.) fruit.

The present study assessed the ability of chitosan-based coatings incorporating savory and/or tarragon essential oils (EOs) to preserve the postharvest quality of kumquats. Changes in weight loss, titratable acidity, total soluble solids, and vitamin C content were determined over 30 days of storage at 7°C. Savory (Satureja hortensias L.) essential oil was characterized by thymol (29.1%), carvacrol (26.6%), and γ-terpinene (24.72%) as major constituents. While, in the tarragon (Artemisia dracunculus L.) essential oil, estragol (81.89%), ß-cis-Ocimene (4.62%), and ß-trans-Ocimene (3.44%) were the main ones. The CH-EOs coatings were effective in reducing weight loss of kumquats fruits during storage. Moreover, the tested composite coatings showed positive effects in maintaining vitamin C and fruits treated with CH-oil coatings retained good sensory acceptability. The obtained results demonstrate the potential of the combined application of chitosan and savory and/or tarragon EOs as a promising postharvest treatment for maintaining the postharvest quality of kumquats fruits.

Characterization of rheological and structural properties of a gum from Balangu seeds.

With the growing interest in all-natural foods, there has been increased study of sustainable natural sources of polysaccharides with suitable functional properties. Lallemantia royleana seed polysaccharide is one such material. Water-soluble polysaccharides were isolated from L. royleana seed to evaluate their chemical structure and rheological properties. The polysaccharide was consisted of neutral (62.9% w/w) and acidic (16.7% w/w) sugars. The backbone of the isolated rhamnoarabinogalactan was composed of (1 → 4)-linked galactopyranose residues. The weight average molecular weight (Mw) of the polysaccharide was 0.777 × 106 g/mol. Rheological behavior of extracted gum was studied at different concentrations (0.1-2.0%; w/v) and temperatures of 5-50 °C. The extracted gum showed typical non-Newtonian and shear thinning behavior at all concentrations and temperatures. However, higher apparent viscosity was observed with increasing gum concentration or decreasing temperature. The quantification of flow activation energy using Arrhenius model showed a decrease from 29,931 to 8339 kJ/mol-1. The mechanical spectra indicated viscoelastic behavior of the gum in all samples. Dynamic moduli increased with increased frequency and G' was always greater than G″, indicating a weak gel system. The results of this study will help to increase potential applications of L. royleana polysaccharide in various food formulations.