Post-harvest Changes In Flavor Of Live Scallop Patinopecten Yessoensis

Live Scallop Patinopecten yessoensis was taken as as the research object, focused on the flavorcharacteristics, and sensory evaluation system and its variation discipline in the trade chain ofliving product were studied systematically. Dry and wet simulated trade chain were constructedbased on the case investigation; flavor changes in the both silulated trade chain were tracing andstudied through sensory evaluation and physiological condition analysis; a sensory evaluationsystem for live scallop was established; physiological condition discipline in the live trade chainwas explored; the correlation between sensory characteristics and the physiological conditionswere analyzed through partial least squares analysis method, and the physiological conditionindicators correlated with the sensory characteristics were selected ultimately. In this study, thesensory evaluation system for live scallop products got initially constructed, which wouldprovide a reference for scientifically characterizing the flavor variation discipline in the livescallop trade chain.(1) First of all, sensory panel of live scallop Patinopecten yessoensis was established anddescriptors were screened.12elected assessors were selected to establish sensory panel from98volunteers;151descriptive words were generated from the panel, and those terms were refinedto33, including: Appearance (Color and Gloss), Odors (Sweetness, Seafood, Fishy, Earthy,Boiled potatoes, Boiled corn, Seaweed, Dairy, Sulfur), taste (Sweetness, Umami, Seafood, Dairy,Earthy, Fishy, Metallic, Sour, Bitter), texture (Fibrousness, Tenderness, Springness, Juiciness,Adhesiveness, Astringency), aftertaste (Seafood, Sweetness, Umami, Dariy, Sour, Bitter,Metallic).(2) Two seven-day simulated trade chains were established through doing fieldwork oncommercial mode of live scallop products from harvesting to consumer’ table:①four days ofdepuration and subsequent3days of transport in wet conditions (in seawater with sufficientoxygen);②four days of depuration and subsequent3days of transport in dry conditions (airexposure with ice-covered). Daily sampling was done and sensory evaluation was conducted bysensory evaluation panel. The results of principal component analysis (PCA) showed thatdepuration did not negatively affect the live scallop, and sensory characteristics of samples inthis stage were embodied in palatable descriptors (Sweetness, Umami, Seafood, Tendernessetc.); samples in late of the wet simulated chain (transportation stage) turned out to beassociated with much less palatable descriptors (Bitter, Sour, Astringent), while dairy flavorappeared in late of the dry simulated chain samples; It is noteworthy that sensory characteristicsof the scallop materials (sample D0) was associated with non-pleasant descriptors, such as Bitter,Sour and Metallic.(3) Physiological conditions of live scallops daily sampled from the above two simulatedchains were analysised. Biochemical indicators included levels of free amino acids, ATP relatedcompounds, glycogen, collagen and pH value; physical indicators included survival rate,adductor muscle yield, condition index, volume of body cavity fluid, cooking loss rate, texture and whiteness. Indicators associated with physiological metabolism showed that: viability ofscallops in the simulated chain was tend to decline, performed as higher adenylate energy charge(AEC) value and higher levels of glycogen in initial of both simulated chains, and higher level ofAla, Arg, Hx, a HxR, Xt and K values in late of both simulated chains; short-term transportation(≤2days) in the dry simulated chain showed superiority than wet simulated chain, which wasrepresented as higher levels of ATP, AEC values and glycogen of samples in dry simulated chainthan samples in wet chain; when extending transport days (≥3days), wet simulated chain couldshow some advantages, which was performed as that levels of Hx, HxR, Xt and K value of drysimulated chain increased rapidly, and survival rate and volume of body cavity fluid significantlydecreased. Analysis of flavor-related components showed that: main pleasant flavor components(Gly, Glu, and glycogen) declined along the simulated chain, while non-pleasure flavorcomponents (Arg, Hx, and Xt) were gradually accumulating. Dry simulated chain showed higherlevels of Gly and glycogen than wet simulated chain. In addition, shear force and whiteness of ofadductor muscle in dry simulated chain were higher than those in wet chain, whereas conditionindex was lower than that of the wet chain.(4) The correlation of sensory characteristics and physicochemical indicators was analysisedby partial least squares2(PLS2), the results showed that: typical sensory characteristics in thesimulated chain of live scallops were sweetness taste, umami aftertaste and dairy odor; mainphysicochemical indicators were levels of Gly, Glu, Arg, ATP, AEC and condition index (CI) anda significant correlation was founded between them. We can deduce that, the above indicatorscould distinguish samples with different flavor quality objectively, thus ensuring minimal flavorquality losses to consumers and, consequently, improve the trade chain.