Chitin's agricultural and preservative miracles: from promoting germination to extending food shelf life

On October 8, 1988, at the Kansai branch meeting of the Japanese Society of Agricultural Chemistry held at Kagawa University, a paper presented by the Kabukichi Bioscience Research Laboratory stated that low-molecular-weight deacetylated chitosan extracted from shrimp shells could promote seed germination and increase yield. The laboratory's director, Tsugita, and advisor, Haruo Fukui, conducted research using "20-day radish," mixing deacetylated chitosan into the soil and coating seeds with it. The results showed that: ① it promoted root and leaf growth in radishes (30%); ② chitosanase was activated in the roots and leaves of the radish; ③ nitrogen and potassium absorption in the roots increased.

The effect of coating seeds with deacetylated chitosan was particularly pronounced. Regarding its mechanism of action, the research laboratory believes that the soil-mixing of deacetylated chitosan with seed coating first activates chitosanase. Then, the chitosanase itself and the degradation products of the deacetylated chitosan promoted nitrogen and potassium absorption, thus exhibiting a growth-promoting effect on leaves and roots. The laboratory plans to conduct further experiments with various plants in the future to confirm the growth-promoting effect of deacetylated chitosan before discussing its mechanism of action in more detail.

On October 9, 1988, at the Japan Home Economics Society's China-Shikoku branch meeting, Yuji Kuwahara et al. from Matsuyama Toun Junior College presented a paper on how deacetylated chitosan can extend the shelf life of pickled foods. They added 0.01% deacetylated chitosan to pickled cabbage in 2% salt solution and stored it in a refrigerator at 10°C, comparing it to the solution without deacetylated chitosan. Generally, pickled foods begin to spoil when the number of bacteria in 1 liter of pickling solution exceeds 1 million. They found that in the pickling solution without deacetylated chitosan, the number of bacteria exceeded 1 million on the third day, while the solution with deacetylated chitosan did not reach 1 million even after 6 days.

They believe that deacetylated chitosan does indeed have preservative effects. Dietary fiber has a variety of functions. Insoluble and soluble dietary fiber have different effects on the human body. In the future, we should not only consider the amount of dietary fiber intake, but also the type of dietary fiber that provides the desired function; that is, paying attention to the quality of dietary fiber is very important. Among lipids, the main components of fats include fatty acids and glycerol. Fatty acids are organic acids with a carboxyl group at the end of their molecules. Although acetic acid can also be considered a fatty acid, the fatty acids in natural fats all have long carbon chains, mostly saturated fatty acids with 4–22 carbons and unsaturated fatty acids with 18–22 carbons.