SHELF LIFE OF THAWED CRUSTACEANS TREATED WITH SULPHITES

Effect of different cooking treatments on the residual level of sulphites in shrimps

Sulphiting agents (or sulphites) are a class of food additives identified in Europe by codes E220-E228. Their addition in crustaceans is permitted with specific legal limits for avoiding the so-called “blackspot” that is a defect that compromises the marketability of these products. High levels of ingested sulphites may cause pseudoallergenic reactions in susceptible people. Moreover, they can exercise mutagenic and citotoxic effects other that destroy some vitamins such as thiamine, folic acid, nicotinamide and pyridoxal. The residual level of sulphites in crustaceans can be considerably affected by the specific method of cooking. In this study, 5 traditional procedures of cooking – grilling, oven, frying, steaming and stewed cooking – were compared to verify their effect on the residual concentration of sulphites in shrimp samples. The analytical determination was carried out using a fully validated and accredited analytical method by ion chromatography with conductivity detection. The results demonstrated that cooking leads to the decrease of sulphites levels in the products, with the highest percentage of reduction (55.3%) obtained by steaming and the lowest using oven (13.9%). The results of this study confirm that the specific method of cooking should be taken into account during “total diet studies” and risk assessment for appraising the effective number of sulphites ingested from crustaceans consumption.

Ultrasound-assisted extraction of guava and papaya leaves for the development of functional shrimp patties

The current study was aimed to evaluate the effects of guava and papaya leaves extract on the antioxidant profile and their outcomes in the storage stability of shrimp patties. Total of seven treatments were prepared by employing guava leaf extract (GLE) and papaya leaf extract (PLE) including control. Both the extracts were employed in the concentration of 1% and 2% each and in combination as 1:1% and 2:2%, respectively. The shrimp patties were kept in ziplock bags at refrigeration temperature, and further analysis was done after 21 days of storage period with intermittent evaluation interval of 7 days. The antioxidant capability of functional shrimp patties was determined by total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP). Higher significant values of TPC, DPPH, and FRAP were observed in the functional shrimp patties enriched with GLE2%:PLE2% at start of the experiment. The physicochemical parameters were observed by hunter color, TVBN, TBARS, and peroxide value (POV). Higher significant values of TVBN, TBARS, and peroxide were observed in the control samples as compared to treatment group GLE2%:PLE2%. The bacterial counts were also higher in control samples as compared to the treatment group GLE2%:PLE2%. The sensorial attributes were observed regarding appearance, taste, texture, odor, and overall acceptability. The maximum scores related all parameters were gathered by control group but significantly lower scores were for the group GLE2%:PLE2%. In conclusion, functional shrimp patties enriched with GLE2%:PLE2% showed better antioxidant capacity, stability, and sensory characteristics during storage.

Monitoring of sulphites levels in shrimps samples collected in Puglia (Italy) by ion-exchange chromatography with conductivity detection

In shrimps the treatment with sulphiting agents is currently the best option for controlling Melanosis, which is a visual defect of the products that compromises marketability. However, sulphites may cause pseudo-allergic reactions in humans. In this study, 210 samples of shrimps were analysed in order to assess the residual levels of sulphiting agents. A quantifiable sulphites concentration was detected in 76 samples, and these concentrations were higher than the legal limits in eight samples. Considering the important pseudo-allergenic effects caused by these food additives, the non-negligible percentage of 3.8% and the high levels registered in non-compliant samples (up to 1174.1 mg kg(-1)), a strong contrast action based on permanent controls is necessary. Moreover, the levels measured in whole samples were up to four times higher than in the edible parts. These results suggest to consider the introduction of legal limits, related to sulphurous anhydride in the whole product.