Products made from sea cucumber are sold in markets in following forms :
Konowata, konoko and dried muscle of sea cucumber are considered delicacy for Japanese. Those who do relish the product willing to pay the high price.
11.1.1 Konowata
The prices paid for the product are very much higher than the price for fresh sea cucumbers. In 1988, the average Tokyo wholesale price was US$50 per kg.
In preparation of konowata, before removal of intestine, the animals are kept in clean seawater for a certain period to empty the intestine before gutting. After the intestine are removed, the contents are squeezed out by hand without breaking the canal, The intestines are washed in clean seawater and rinsed. The viscera is salted using 10–15% salt by weight of the raw viscera. One-third of the total salt are added to the product first to extract water from the body. After draining occurred, more salt is added, and mixed thoroughly for five and half hour. The mixture is put into a wood barrel and cover with a lid to allow the product fermented. Occasional stir might need during the fermenting period. The finished product is packed in bottles and distributed to retailers. The nutritive value of the product are 76.5% water, 9.3% protein, 1.3 fat, 0.5 carbohydrate and 12.4% ash. The price of konowata is paid partly on the length of the intestines. Longer intestines command higher price.
The intestines, after removed from the animal, can be kept in cold storage for a considerable time before processing or waiting for a period of the high price market.
11.1.2 Konoki
This product is the most expensive product prepared from sea cucumber. It commands the price at US$200/kg. The product is not common mainly because it is difficult to procure. The product does not weigh more than 2.5% of the body weight during the spawning season. More over during out spawning season the gonad is much smaller, only a small fraction of a per cent of body weight.
Removal of gonad as well as intestine from sea cucumber does not to kill animals. Small incision on body wall is enough to remove the gonad and intestine. The cut made on the body wall will heal in 5–7 days. The intestine will regenerate, and the same quality or even more can be obtained in the following year.
11.1.3 Dried muscles
This product is made from the longitudinal muscles of sea cucumber. It is tender and taste like high quality clam meats. Beside Japanese and Chinese, the product is also palatable to American and European. It is a high potential products for those markets.
The removal of the long, thin longitudinal muscles is facilitated by placed the sea cucumber in pure, clean seawater to contract or shortening the muscles. The muscle are preserved in brine, and sold in market in canned products.
This product used in gourmet soups or other delicacy chinese dishes. It is the most common product made from sea cucumber. Price paid for the beche-de-mer varies greatly depending on the species of sea cucumber used and the care given during processing. The best species are large and the body walls are thick.
Factors that may influence the quality of the product during processing are :
The sea cucumber takes a long time to die and the body disintegrates before death. It should be killed instantly by immersion in boiling seawater to preserve its wholesomeness.
Scum from fine mud and debris on its body wall have to be removed without loosing the nutritive matter of the body wall. Partial decomposition or softening of the outer wall facilitates removal of scum.
11.2.1 Handling
Efficient handling practices are important to maintain cleanliness and hygiene on board, reduce losses during processing and improve the market value of the product.
As soon as the sea cucumber is hauled up on board, a 2–3 cm slit is made near the cloaca. Pressing the body wall near the oral region facilitate rapid evisceration of gut and entrails. Any water that may remain inside the body is also squeezed out.
Plastic containers with a smooth interior are suitable for holding sea cucumber on board. The use of ice is not recommended because the body wall of the sea cucumber may damage. To prolong holding time during transportation, seawater is changed every 12 hours.
11.2.2 Gutting
The first step in preparing tripang is gutting of the sea cucumber. The incision for gutting is usually made on the ventral side of the animal starting at the anus and going halfway to the anterior end of the sea cucumber. The opening makes it possible to thoroughly clean the inside cavity. Careful gutting is essential because of the gut is normally filled with mud or sand. The imperfect removal of a mud-filled intestine greatly reduces the value of the product. Some species eviscerate eventually during handling, but to obtain the best product, even these species should be hand-gutted.
11.2.3 Cooking
After cleaning, the sea cucumbers are sorted by size and boiled for 10 mins to 1-½ hrs. Large specimens might take longer cooking time. Boiling serves several purposes besides tenderizing the meat. Firstly it kills micro-organisms which would cause spoilage before drying could be completed. Secondly, boiling contract the sea cucumber to the desirable thickening of the body wall. Thirdly boiling reduces the free water in the tissues, thereby speeding drying process. Fourthly boiling may reduce the amount of toxin in toxic species, and the finished product will be less salty.
When thoroughly cooked, the sea cucumber give out a characteristic cooked odor. Overcooking may cause the sea cucumber to blister and become porous like sponge. During cooking, the shape of the sea cucumber should not deform. If the animals bloat up due to expanding air in the body cavity, they should be pierced to release the air. During cooling process, the bodies should be straightened. Cooking is achieved when the animals have attained a blubber-like form. They bounce like a ball when dropped on the floor.
The skin of sea cucumbers contains tiny calcarious deposits. In certain species limy grains are abundant. it becomes chalk-like deposits when dried. This pigments have to be removed to improve its market value. Some processors remove the skin. In some species the skin comes off easily after the first cooking. Removal of the outer layer skin can also be facilitated by burying the cooked sea cucumber for 12–18 hrs in moist sand. By action of bacteria the outer layer containing the chalky spicules are decomposed. It peels off easily when touched leaving a pasty material on the hand. A brush is also may use to clean the outer skin. In Southeast Sulawesi, the sea cucumber is mixed thoroughly with papaya leaves. The acid from the papaya leaves will remove the limy grain. The sea cucumber at this stage is normally cylindrical in shape, rubber-like, wrinkled and ash grey in color.
The sea cucumber is then washed, rinsed and reboiled in seawater for 30–45 minutes. All remnants of bacteria that decomposed the outer layer are killed.
11.2.4 Drying
Drying on the ground makes inferior product because drying process is slow and not stay clean. To make a good quality of the beche-de-mer, the product should dry on platforms off the ground or in driers. This does not only give a consistent results, but speeds drying and permits processing during inclement weather.
After boiling, cleaning and reboiling, the sea cucumbers are spreaded on drying platforms or wire mesh trays. It may take from one to three weeks for sun dry. Drying rate depends on thickness of the body walls, the surface area exposed, the temperature, and relative humidity. Percentage losses of weight and moisture content of sea cucumber during drying process is given in Table 10.
In Japan the product are roasted at 70 C before drying. Smoke driers could be made using and galvanizes sheet in which trays of sea cucumbers are arranged in vertical rows above drier. This is usually a 200-liter drum kept horizontally, with wood-fire, all housed in side and enclosure.
The sea cucumbers are dried until they appear brittle, having a water content of 8–10 per cent. Dried sea cucumber can be stored for years. However, since the dried sea cucumber tend to reabsorb water easily, it needs to be re-dried periodically to prevent spoilage.
11.2.5 Packing
On completion of processing, the product is graded on the basis of length, appearance, odor and weight per kg. Packing materials are copra sacks, jute-hessian sacks and plastic bags. To avoid the re-drying, the vacuum pack may be a necessity.
The good quality of product should have uniform, non-distorted shapes. It should be hard and dry, a moisture content allow up to 20–30 per cent. The product should have a pleasing odor and be free of dirt.
