Abstract
Kinnow’ mandarin fruits are highly perishable and have a shorter shelf life due to their higher
moisture content and soft rind texture. Chilling injury can easily damage them when stored
100 under low temperatures after harvest. The fruit may become water-stressed when stored under
suboptimal conditions, leading to rind disorders. ‘Kinnow’ mandarin fruit are also susceptible
to off-flavours development when coated with a higher gloss coating, leading to anaerobic
respiration and ethanol build up during storage. These problems affect their eating quality and
market value, resulting in postharvest losses. Chemical fungicides have been used successfully
105 for citrus decay control and quality preservation. However, there are limitations to their uses
due to consumer and environmental safety concerns. As a result, a safe strategy to impede these
issues is of great interest. The application of edible coatings is a technological advancement
considered as a potential solution for the shelf-life extension of ‘Kinnow’ mandarin fruit to
their easy use, affordable and biodegradable benefits. To the best of our knowledge, there is no
report on the application of Aloe ferox gel for the postharvest preservation of horticultural
crops.
This study characterized Aloe ferox gel (AFG) reinforced with cellulose microfibre (CMF) and
evaluated the compatibility of AFG sorely for postharvest preservation of ’Kinnow’ mandarin
fruits in simulated export and retail conditions. For film’s characterization, Fourier-transform
infrared spectroscopy (FTIR) results indicated the presence of uronic acid, mannose,
galacturonic acid, phenolics, cellulose, lignin, hemicellulose, polysaccharides, and glycerol in
the composite edible films. Films formulated from 30%AFG&0.15%CMF were light and
transparent with higher tensile strength and moisture content, lower WVP and solubility than
edible films with 50%AFG&0.15%CMF. Scanning electron microscope (SEM) results
revealed a compact structure with fewer pores for 50%AFG&0.15%CMF than
30%AFG&0.15%CMF. The increase in the concentration of AFG significantly influenced the
edible films' morphology, physical and mechanical properties. There were no significant
differences in the film's antioxidant capacity and total phenolic content.
For the postharvest preservation of ‘Kinnow’ mandarin, fruits were treated with AFG at 30%
and 50% (w/v) and stored at 5 ± 1 °C and 80-85% (RH) for 6 weeks (42 days). Analysis was
conducted at 2-week intervals of cold storage and 3 days of shelf life at 21±1 °C and 50-55 %
(RH). AFG 30% treatment significantly (p< 0.05) reduced water vapour permeability (WVP)
of fruit rind to 2.210 × 10-5 g.mm m-1 h-1 Pa-1 and respiration rate (RR) to 15.65 mLCO2Kg-1hvi
compared to the control group, with WVP of 2.636 × 10-129 5 g.mm m-1h-1Pa-1 and RR of 19.88
mLCO2Kg-1h-1. AFG concentrations notably reduced rind pitting incidence to 5.56% for AFG
30% and 5.55% for AFG 50% compared to the control (66.66%). Furthermore, AFG 30%
exhibited the lowest electrolyte leakage at the end of the storage period (42.41%) compared to
47.77% for the control group and 46.54% for AFG 50%. SEM analysis of the coated fruits
134 revealed a complete coverage of lenticels on the fruit rind, suggesting an alteration in the fruit's
physiological responses, such as respiration and transpiration. In conclusion, AFG, particularly
at a 30% concentration, offers a promising alternative for postharvest preservation of 'Kinnow'
mandarins. Further research should explore its applicability to other horticultural crops.