Use coconut water instead of formalin (formaldehyde) in prolonging the freshness of vegetables. The use of coconut water is simpler, safer, and more economical use than using formalin, which may scare vegetable buyers.
In a demonstration by researchers at the College of Agriculture, University of the Philippines Los Banos (CA-UPLB), string beans dipped in fresh coconut water for at least two minutes stayed fresh and marketable even up to four days after harvest.
The shriveling or drying of the beans was also reduced.
The CA-UPLB researchers said that the coconut water contains cytokinins or hormones responsible for retaining the green color (chlorophyll) of stringbean pods.
source: CocoScope, July-September 1999