IMPACT OF PEEL COLORATION ON INTERNAL QUALITY OF KINNOW MANDARIN (Citrus nobilis Lour x Citrus deliciosa Tenora) AT EARLY RIPENING STAGE

Abstract

At earlier maturation, Kinnow mandarin color-break fruits were analyzed for internal quality. Ten fruits were harvested from dark green to fully red or yellow colored at field on visual observation and arranged in order of dark green to deep red or yellow through Chroma meter after being numbered as 1 to 10. Three aliquots were analyzed as per replicate. In red colored fruits juice, a decreasing trend of titratable acidity, ascorbic acid and total soluble salts were found with increasing pattern of sugars, total soluble solid and pH. Similarly in peel, low chlorophyll contents and highest carotenoids were recorded in red colored fruits. Total phenolic contents in juice were similar with declining trend in peel from green to red colored fruits. In juice both flavonoids and flavonols were constant but in peel flavonols increase were noted in red colored fruits. Total anthocyanins exhibited an increasing trend in red colored fruit for both, the peel and juice. Antioxidant activity was increased in juice and decreased in peel for red c olored fruits. Nutritional values of green color peel fruits are alike those of red colored, but with reduced sugars, and sweetness were duly noted regarding their domestic consumers acceptance. Green color fruits have more ascorbic acid, polyphenols and r educing sugars are equally valuable like red colored Kinnow, thus both types are of Kinnow are best for the purpose of export .

Impact of varying agrometeorological indices on peel color and composition of Kinnow fruit (Citrus nobilis Lour x Citrus deliciosa Tenora) grown at different ecological zones

“…Described protocol was used to estimate chlorophyll and carotenoid contents in Kinnow fruit peel. Absorption of individual sample at 663, 645, and 470 nm on a spectrophotometer (SP‐3000 Plus model, Optima, Tokyo, Japan) was checked.…”

“…Method was followed to estimate ascorbic acid (AA) by using given formula. Absorbance was checked at wavelength 243 nm on spectrophotometer.…”

“…Folin–Ciocalteu (FC reagent) method was used to measure total phenolic content (TPC) . Gallic acid equivalent (GAE) was obtained by using different concentrations of gallic acid and communicated as milligrams of GAE per kilogram of peel FW . Standard curve of gallic acid is calculated by given formula.…”

“…Color is also used for determining maturity index and fruit inner quality attributes . Color‐break in Kinnow mandarin changes fruit internal quality parameters and is still used as a tool in judging the maturity and quality of fruit in the domestic market . In advanced countries, color along with citrus fruit's other quality attributes are used for fruit harvesting and marketing at domestic and external level …”

“…Color development is also linked with change in peel composition, depending on external environment. Upon color‐break to afterwards, chlorophyll contents in peel start to decrease and color imparting contents like carotenoids and anthocyanins show an increasing predisposition . Similarly, polyphenols and antioxidants in peel, along with fruit peel firmness are also changed with color development; all of them are swayed by external environment .…”