When the hard shell of a tamarind pod is peeled off, it reveals a reddish-brown coloured pulp. While the sweet and mildly tangy pulp is a refreshing snack and can be used for cooking, juice or even candy, the seeds -- which are the by-products -- were always regarded as waste.
Despite this, about a decade ago, one man looked at the tamarind seeds differently and took them on as the topic of his research. Today, thanks to the efforts of Assoc Prof Woatthichai Narkrugsa from the Faculty of Food-Industry of King Mongkut's Institute of Technology Ladkrabang, he and his research team extract xyloglucan -- hemicellulose that acts as a gelling and thickening agent -- from tamarind seeds. The gelation properties of tamarind seeds can be used for a wide range of applications that benefit the food, textile, medical, colour, paper and cosmetics industries.
"My initial aim was to add value into the valueless tamarind seeds," he said.
Woatthichai became interested in tamarind seeds in the early 2010s after he came across a research article from a journal in Germany about the benefits of tamarind kernel powder.
"It raised a big question in my mind. I wondered why German researchers experimented with the seeds when they did not have tamarind trees. In Thailand, we have lots of tamarinds but no one had done any R&D on it," he recalled.
Tamarind is one of Thailand's staple economic plants and the trees grow in the wild throughout the country. According to statistics from the Department of Agriculture Extension from last November, tamarind trees are present in at least 54 provinces and cover a total cultivation area of about 194,000 rai. The largest producer of tamarind is Phetchabun province, which sees annual yields of 47,101 tonnes, or almost half of the total tamarinds harvested in the country.
Woatthichai and his research team had been searching for a tamarind producer and eventually found Pinphet -- a company in Phetchabun -- had the capacity to develop a new production line to produce tamarind seed powder.
Below Tamarind seeds are cracked open to reveal light yellow kernels before they are ground into powder. (Photos: Thailand Science Research and Innovation)
Assoc Prof Woatthichai Narkrugsa. (Photo courtesy of King Mongkut's Institute of Technology Ladkrabang)
Pinphet produces and distributes many types of tamarind products, including fresh tamarind, seedless tamarinds and processed tamarind snacks. However, it had about 150 tonnes of leftover seeds every year.
"Before I worked with Woatthichai [around 2014], I sold about 5 tonnes of tamarind seeds a month for exporters who shipped containers full of them to Japan and China," said Waratchaya Junjit, the owner and managing director of Pinphet.
She sold the seeds at prices ranging between 3-5 baht per kilogramme. The price was low but it was better than nothing, she said. Since her company produced tonnes of tamarinds, she wanted to make the most use of the fruit. She also hoped that working with Woatthichai would lead to innovation and would help her business stand out from other tamarind factories.
Knowledge of tamarind kernel powder is not new as in the past, local artists used the powder as a glue for painting murals on walls of prayer and ordination halls in temples. The material helped murals last longer and kept the colours vibrant for centuries. Meanwhile, in rural areas, people cracked seed hulls and consumed roasted white kernels as nuts. Yet it is not a popular snack because cracking the seeds takes time and effort.
In India, the gum extract from tamarind seeds has been used as a substitute for starch in cotton textiles since 1943. Moreover, the gel property has also been used in the food industry in Japan, South Korea and China for more than 50 years.
Left Tamarind gelato from Pinphet factory is among prototype products that use kernel powder extract as pectin.
Phathai silk bags from Graccy Group. The bags are coated with tamarind kernel powder extract.
For advancing scientific knowledge about the seeds in Thailand, Woatthichai was the pioneer. He received a fund from Thailand Science Research and Innovation (TSRI) around 2014 and that marked the start of his project to find a cost-effective method to extract xyloglucan or tamarind gum from tamarind kernel powder and study the gel-forming properties. (The Intellectual Property Department granted a petit patent for his research in 2016.)
What Woatthichai discovered was that the gel property is strong and contains dietary fibre. In fact, it is a natural non-toxic polysaccharide that is edible.
"Instead of selling tamarind seeds for export at a couple of baht per kilogramme, the seeds can be extracted for xyloglucan and sold at prices ranging from 5,000 baht to 12,000 baht a kilogramme depending on purities," he said.
The tamarind gum can also be a replacement for pectin in the food industry. When the gelling agent is produced within the country at low costs, it can help reduce the need to import pectin worth more than 300 million baht every year.
Woatthichai then applied the tamarind gum for various prototype products, including tamarind jellies and tamarind gelato. His research team also produced edible films and coatings for export fruits and mixed the tamarind kernel powder extract with chitosan from shrimp shells. They called the application "chitam" and sprayed it as a coating on fresh mangoes and bananas for export. The fruits were kept in cold storage for seven days in a controlled condition and the result was impressive -- the fruits were still fresh.
The researcher also used chitam to develop a biofilm for dressing wounds to improve the healing process. Moreover, Woatthichai and his team conducted a clinical test with the Tambon Health Promotion Hospital of Klong Luang Phaeng in Chachoengsao's Muang district back in 2011 in which the biofilm was used for curing a pressure ulcer that was present on the foot of a diabetic patient.
"The patient's wound was healed within 11 days. We were glad that the patient did not have to lose his foot," he said.
Based on his research on xyloglucan applications, Woatthichai won an award for innovation in Thailand. He also received the Brussels Eureka Innovation Award "Chevalier Level" by the high commission of the Innovation Award and a gold medal as an outstanding researcher in Belgium in 2015. Last but not least, his work also won him a special medal from the Euro-Business-Haller and Haller Pro Inventio Foundation of Poland.
At present, Pinphet, the first company that worked with Woatthichai, produces tamarind kernel powder and powder extract. Besides producing the tamarind gelato prototype, the company is also planning to introduce crispy snacks based on the tamarind kernel powder.
Phathai silk bags from Graccy Group. The bags are coated with tamarind kernel powder extract.
lEFT Challetip Tippanet shows her company's bag to House Speaker Chuan Leekpai at an expo in the parliament.
For the textile industry, Grace Group uses tamarind seed extract for nano-coating some of its women's silk bags and purses. The group purchases silk textiles from women's weaving groups in Nakhon Ratchasima, Khon Kaen and Nan and then produces the products in another community in Roi Et.
"I personally like silk textiles and want to make fashionable silk products that people can use daily," said Challetip Tippanet, the owner and managing director of Graccy Group.
She also wants her products to be durable and stay in good condition for as long as possible.
"After coating tamarind seed extract on our silk bags, I was impressed with the result. The coating helps make the colours vibrant and slow deterioration of the fabric," she said.
The nano-coating technology also adds value to her products and makes them water-resistant, which allows her to sell them for at least 20% more than non-coated silk bags.
Last but not least, Woatthichai is also working with another entrepreneur which he declined to name. The company will produce products that are integrated with the tamarind gelling agent such as biofilms for healing wounds. He said the products will be introduced in the near future.
"I am proud of what we have done. My research has had benefits for various sectors. It also fits under the zero waste management concept and the self-sufficiency economy," said Woatthichai.
