International Journal of Agriculture, Environment and Biotechnology
Citation: IJAEB: 8(1): 83-87 March 2015
DOI Number: 10.5958/2230-732X.2015.00011.X
©2015 New Delhi Publishers. All rights reserved
11 (OK)
HORTICULTURE
Seasonal variations in peel colour in relation to fruit
development of grapefruit ( Citrus paradisi Macf.)
Sukhchain Singh*, Pushpinder Singh Aulakh and Parmpal Singh Gill
Department of Fruit Science, Punjab Agricultural University, Ludhiana – 141004, Punjab, India.
*Corresponding author: boparai.sukhchain@yahoo.com
Paper No. 295
Received:
Accepted:
Published: 25 March 2015
ABSTRACT
The studies on seasonal variations in peel colour of grapefruit cv. Star Ruby were carried out in order
to explain the relationship between fruit growth and colour development. The fruit diameter of the
grapefruit increased from 90 days after fruit set to the maturity of fruit. The seasonal variation in
fruit diameter was recorded 12.83% during fruit development. The increase in a* coordinate, which
represented the gradual loss of greenness, continued until mid-November at 210 DAFS. Calorimetric
coordinate b* values always remained positive and increased until the fruit maturity and showed
yellow tinge. The hue angle values decreased continuously from start of sampling to the harvest of fruit
with appearance of pinkish-yellow tone. Seasonal variation in the hue angle was recorded 26.80%. The
negative correlation was observed between hue angle and the fruit development with the advancement
of fruit maturity. However, studies have reported positive correlation was recorded between colour
space values (L*, a*, b* and C*) with fruit development. The maximum seasonal variation was noted
in colour parameter a* (CV = 189.99%) and minimum seasonal variation was noted in L* (CV = 9.42%).
Highlights
  • ȱ Grapefruit peel colour changed from green to pinkish-yellow at maturity.
  • ȱ Higher seasonal variation in colour parameter a* and hue angle were recorded.
    • Keywords: Grapefruit, colour, fruit development, correlation, seasonal variations.
    Citrus fruits occupy a key position among the tropical
    chlorophyll degradation and pigment biosynthesis.
    and sub-tropical fruits of the world (Jawandha et
    The colour of fruit is derived from natural pigment
    al. , 2014). Among citrus fruits, grapefruit ( Citrus
    and changes as the fruit proceeds towards maturity.
    paradise Macf.) is consumed widely in today’s health
    The primary pigments imparting colour quality are
    conscious world as a protector against cardiovascular
    the fat soluble chlorophylls, carotenoids and water
    diseases and cancers (Kiani and Imam 2007). Under
    solubleȱanthocyanins,ȱflavonoids.ȱGrapefruitȱshouldȱ
    sub-tropicsȱ ofȱ India,ȱ theȱ mainȱ floweringȱ periodȱ ofȱ meet some quality standards such as colour intensity
    grapefruit occurs during the month of March with a
    and size at harvesting to ensure good returns to
    winterharvestperiod.Harvestmaturityforgrapefruit
    growers.
    has been based on visual and destructive tests. Palma
    FruitcolourisimportantharvestindexwithL*,a*and
    et al. , (2011) described that ripening occurs in the
    hue values being the best parameters to discriminate
    finalȱphaseȱofȱfruitȱdevelopment,ȱandȱinvolvesȱdeepȱ
    amongȱ differentȱ maturityȱ stagesȱ (Mercado-Silvaȱ et
    metabolic changes in the biochemistry, physiology
    al. , 1998) and the colour measuring instruments are
    and gene expression of the fruit in the form of