“Butter Crab”: an environment‐induced phenotypic variation of Scylla paramamosain with special nutrition and flavour

Abstract

An "abnormal" female Scylla paramamosain, named "Butter crab" (B_♀) is more popular than wild-type mud crab (CK) with people. Histologically, "butter crab" ovaries are partially degraded, with full of yellow oily substances in body. Composition of the essential nutritional components is quite similar in "butter crab" and CK. In a comparison of fatty acids, B_♀ is richer. A comparison of flavour amino acids and nucleotide in muscle showed that sweet amino acids and bitter amino acids in B_♀ is lower than CK_♀, but umami amino acids are significantly higher in B_♀. However, the umami amino acid content in the gonads is significantly less in B_♀ than CK_♀. Moreover, umami nucleotides in B_♀ muscle is significantly higher. From the perspective of EUC evaluation, the umami taste of CK_ ♀ gonads is strongest, followed by B_ ♀ gonads. In the hepatopancreas, the umami taste ranks CK_♀> B_♀ >CK_♂, and there are no significant differences among muscles in the three groups. In conclusion, the characteristics of "butter crab" are more fragrant and nutritious, with sweet and umami taste. The article systematically scientifically analysed the nutritional composition and flavour characteristics of "butter crab", providing a novel insight for development of S. paramamosain industry. K E Y W O R D S"Butter crab", flavour, nutritional composition, Scylla paramamosain

Overwintering behaviour affects distinctive flavour of mud crab Scylla paramamosain in commercial farms

“…Scylla paramamosain , a most valuable crustacean, has been widely cultured in the coastal region of southern China (Wang et al, ; Wang, Tang, Wei, Mu, & Wang, ; Ye et al, ). In China, due to their large size, high meat yield, delicious meat and high market price, mud crab production in 2017 has reached up to 151,976t (National Bureau of Statistics, ; Wang et al, , ). The culture cycle of S. paramamosain is focused on the cultivation from April to May, harvest from November to December and harvest from May to the next year.…”

“…The market price of S. paramamosain is mainly determined by the factors such as flavour, market time, origin, gender and weight, among which flavour is the most critical factor affecting the price of crab. There are many elements influencing food flavour, such as the growing environment, feed and intestinal microorganisms can lead to differences in nutritional composition and flavour characteristics (Shao, Wang, He, Wu, & Cheng, ; Tao et al, ; Wang et al, ; Zhuang, Wu, & Wang, ). Free amino acids and nucleotides are important non‐volatile taste substances, which play a very important role in the taste of crabs (Chen & Zhang, ; Tao et al, ; Wang et al, ).…”

“…Salt, sweet, sour and bitter are the four basic tastes of food, while umami is increasingly recognized as the fifth basic taste (Marcus, ; Ninomiya, ; Nishimura & Kato, ). Umami is a very important flavour characteristic of crab aquatic products (Latyshev, Kasyanov, Kharlamenko, & Svetashev, ; Shao et al, ; Wang et al, ), a folk saying in China that ‘other dishes have no taste when the crab meat is on the table’. In addition, Nelson et al () found that two G protein‐binding receptors, T1R1 and T1R3, exist on the surface of taste cells, which can make people feel the taste of 20 L‐amino acids, but have no effect on D‐type amino acids and other substances.…”

“…The results provide a theoretical basis for umami as the fifth basic flavour. There have been many reports on the main flavour substances of Marine aquatic products, among which free amino acids and free nucleotides play an important role (Musaiger & Alrumaidh, ; Wang et al, ). In free amino acids, Glu and Asp are characteristic amino acids with umami, and umami can also be produced by 5'‐monophosphoric acid taste nucleotide disodium salt, such as IMP, GMP, AMP and XMP, which are usually high in the content of aquatic products (Gokoolu & Yerlikaya, ).…”

“…Sweetness is another major flavour characteristic of crabs. Most amino acids, such as Gly, Ala, Ser, Thr and Pro, are sweet (Nishimura & Kato, ; Wang et al, ; Zhao, Wu, Wang, Wu, & Wang, ). However, the edible parts of S. paramamosain are all slightly bitter, which is mainly due to the action of some bitter amino acids, including Arg, Tyr, Trp, Lys and other amino acids (Tao et al, ; Wang et al, ).…”