The ancient medical book recorded:" If eat crab with perimmons together, it can make people suffer from diarrhea." The reason is that the crab includes the abundent protein, and persimmons contain a lot of tannic acid, the two eat together, will solidify and harden. In addition, the crab and persimmons all belong to the cold and cool things, at the same time can easily cause to uncomfortable if take it excessively (Da Zha, 2004).
Factors cause the crab and persimmons combination choice:
1. Taking persimmons before or after crab meal, especially during Chinese New Year.
2. Taking persimmon as appetizer and follow by a meal with crab.
3. Drink persimmon juice with crab meal.
4. Taking persimmon salad with crab soup.
5. Taking persimmon cake follow by a chili crab meal.
Crab contains the abundent protein and persimmons contain a lot of tannic acid. The tannic acid from persimmons inhibits the secretion of the digestive acids required for protein digestion. One tannin molecules binds two or more peptide groups, by formation of cross-link between the protein chains. The level of cross-linkage depends upon the number and accessibility of protein carbonyl groups per protein molecule and the relative concentration of the tannin. Tannin reacts with protein will form turbidity and a medium, coagulate the protein. The protein-tannin coagulate form will accumulate in stomach (D.K.Salunkhe, 1990).
Undigested protein then putrefies owing to the constant presence of bacteria in the digestive tract, the bacteria in the alimentary canal get all the nutrients release waste product as toxins to the body. The bloodstream picks up toxins from the putrefied mess as it passes slowly through the intestines, and these toxins in turn cause rashes, hives, headaches, nause and other symptoms commonly branded as allergies. This putrefaction is the primary cause of all sorts of digestive stress, including gas, heartburn, cramps, bloating, constipation, foul stools, bleeding piles, colitis, stomachache and diarrhea (Daniel Reid, 2006).
Suggestions on how to prepare the food to enable safety consumption:
1. Peel the persimmon before eat with crab, because most of the tannic acid comes from the peel.
2. Since the property of crab is cold, it should be eaten with dipping vinegar or drinking wine to warm the stomach and eliminate the cold, to disinfect and eliminate the poison.
cold is refer to the yin in tradition chinese medicine, please click Food combining guidlines to have more details about yin/yang balance in food combination which is similar to the acid/alkaline in chemistry aspect.
3. When suffer crab toxin occasionally, drink fry purple perilla juice or smash wax juice to diminish the effect.
4. It is better to eat one to two pared persimmons after a meal, so it will not produce any chemical effect in the stomach (Donald, 2004).
5. Crabs should be dipped in ginger vinegar before eating to kill the bacteria (Donald, 2004).