Abstract:
Influence of carboxy methyl cellulose (CMC) and guar gum based silver
nanoparticles containing coatings was studied on the postharvest storage stability of
kinnow mandarin (Citrus reticulata cv. Blanco) stored at 4 oC and 10 oC (85-95%
relative humidity) for a period of 120 days. Physicochemical qualities,
microbiological evaluations, quantities of three major aroma compounds (limonene,
linalool, γ-terpinene) and sensory attributes were monitored after every 15 days of
storage. Microbiological quality was assessed by monitoring the principal spoilage
microbes (yeast and moulds, psychrotrophic bacteria, E. coli, Salmonella and
Staphylococcus aureus). Sensory evaluation was carried out using 9 point hedonic
scale by a panel of 25 experienced penalists for peel colour, flesh colour, juice colour,
fruit texture, fruit taste, fruit flavour and overall acceptability. Overall, the results
revealed an increase in peel pitting, total soluble solids (TSS), total sugars, reducing
sugars, non-reducing sugars, pH and weight loss in the fruits, but this increase was
comparatively less significant in coated fruits stored at 4 oC. Ascorbic acid, total
phenolics and antioxidant activity were significantly enhanced in coated fruits stored
at 4 oC. Titratable acidity was significantly decreased during storage except for coated
kinnow stored at 4 oC. In control samples stored at 10 oC, a high intensity of fruit
rotting and no chilling injury was observed. Total aerobic psychrotrophic bacteria,
and yeast and moulds were noticed in all treatments during storage, but the growth
was not significant in coated fruits at 4 oC. Staphylococcus aureus was not noticed in
coated fruits stored at 4 oC, while E. coli and Salmonella were not found in any
treatment during storage. Limonene, linalool and γ-terpinene concentrations were
significantly reduced during storage in uncoated, and those kinnows coated and stored
at 10 oC. However, the storage did not alter the qualitative aroma profile of kinnow.
Hedonic scores of sensory evaluation panel appeared to correlate well with the aroma
profile and manifested the GC-MS results. Based on the present study, the quality of
kinnow fruit can be kept good for 4 months, when stored at 4 oC and for 2 months at
10 oC.
