Abstract
Chitosan coating is one of excellent technique to prolong shelf life of fruits. Many studies
reported that chitosan incorporated with plant extracts such as guava leaves, papaya seeds,
basil leaves, clove buds and cashew leaves can be used for coating fruits. The previous
research found that cashew leaf extracts expressed the biological properties such as
antioxidant, antimicrobial, analgesic and anti-inflammatory. Currently, lime fruit is one
of the economic crops in Thailand and its marketing is limited due to climate change and
diseases, which lower the quality of fruits. This research aimed to study and compare the
antimicrobial properties of cashew leaf extracted with water and 70% ethanol. The effect
of chitosan coating incorporated with cashew leaf extracts on lime (Citrus latifolia Tanaka)
fruits qualities (firmness, color, TA, TSS, weight loss, vitamin C, and antioxidant property)
during storage was also investigated. The result showed that 10% ethanolic and aqueous
extracts could be inhibited the growth of Aspergillus niger. An ethanolic extract had lower
minimum inhibitory concentration (MIC = 6.25 µg/100µl) than the aqueous extract (12.5
µg/100µl), but the had similar minimum fungicidal concentration (MFC = 25 µg/100µl).
For application part, lime fruits were separated into four groups: uncoated (control), coated
with 2% chitosan, 2% chitosan combined with 5% ethanolic extracts (CLE), and 2%
chitosan combined with 5% aqueous extracts (CLW). All lime fruits were stored at 15°C, 90%
RH for 42 days. The coated fruits combined with 5% CLE showed the higher firmness, color
(a*), TA, vitamin C content, antioxidants activities, and the lower weight loss and TSS than
those of other treatments. Furthermore, coating fruits with 5% CLE presented the inhibitory
efficiency against the growth of A. niger in inoculated lime fruit as it showed the lowest
percent disease incidence and disease severity index. Cashew leaf extract can be one choice
of a natural antifungal agent which can be used in agricultural produce.
