IS MAKING TAPAI A FERMENTATION PROCESS?

Recently, by chance I came to read a chapter entitled"Tapai processing in Malaysia: A technology in Transition" by Zahara Marican and Yeoh Quee Lan in a book edited by K H Steinkraus entitled "Industrialization of indigenous fermented foods". The authors discussed in general about making tapai in Malaysia.

There were a few interesting points made by the authoress such as on page 252 which I quote "tapai fermentation is not an anaerobic process and this partly accounts for the low alcohol content. Furthermore the fermentation is normally arrested before all of the sugars are fermented, as the desired end product should not be alcoholic if it is to be consumed by those opposed to alcohol consumption for religious or other reasons"

In the above statement I only want to direct to the points that:
1 Tapai fermentation is not anaerobic
2 Partly account for the low alcohol content
3 fermentation arrested before all the sugars are fermented

From the above statements I seem to see that even within the same sentence or paragraph the two authors contradict themselves. While in the early statement they deny tapai is a fermentation process but in the later sentences they admit that the fermentation process is arrested

I would like to make a point here that in the production of tapai it it involves yeasts and fungi which are capable of living aerobically or by fermentation. In the beginning stage of tapai production, enzymes are released to release the free sugars. This explains in the process of the enzyme hydrolysis why the tapai is sweet. At this stage it may or may not be aerobic.
However, when alcohol are produced by the yeasts by metabolizing the sugars in the absence of oxygen, it is definitely fermentation. In fact it is a good example of the classic traditional fermentation

One must be aware that tapai production is slightly different compared to wine or beer fermentation, even though sugars are used and alcohol are produced. In tapai fermentation it involves the concept of solid substrate fermentation. Each of the cooked pulut or ubi is coated with a thin layer of viscous liquid which makes oxygen diffusion and penetration difficult and thus setting the environment for alcohol fermentation. The action of the sugar molecules with the liquid caused rheological changes making it sticky or viscous. This is attributed to the interaction of the hydrogen bondings between the sugar molecules and water molecules

The low alcohol content achieved by some makers of tapai is attributed to the slightly open or not tight packing and high room temperature which would result in the vaporization ot volatilization of alcohol to the environment. After all the alcohol as fermentation products are short chain and gave a lower evaporation or boiling point

The sad point I want to make here is that the article has not changed much despite advanced understanding of the biochemistry and biotechnology of the fermentation process. The chapter would have been more interesting rather than traditionally detailing the usual methods of making tapai and listing the various microorganisms.

It is in this aspect why I feel that until the understanding of fermentation technology is fully carried out, there is really no transformations in the technology of tapai making and the industry will still lag far behind

ADDITIONAL NEWS
---------------
For those interested too see how to produce tapai or interested in making money out of tapai, please go to the following website:

www.tapai.com.my

The site is intersting as not only it gives tips to making tapai but valuable information in trouble shooting tapai making process