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ABSTRACT

Pork loin and leg were evaluated 24h after slaughter and during refrigerated (5°C) and frozen storage for microbial counts, pH, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and bioactive amines. Spermine was the prevalent amine in fresh pork loin and leg, followed by spermidine and agmatine. During refrigerated storage, pH, TVB-N, mesophilic and psychrotrophic counts increased and no changes (p<0.05) were observed on polyamines; however putrescine, cadaverine and histamine were produced and accumulated throughout storage. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) for all parameters indicated a shelf life of 8days for both cuts, which was also coherent with safety regarding histamine levels. During frozen storage, there was no change on amines and pH, TVB-N decreased, and TBARS increased. None biogenic amine was produced. PCA and HCA were not able to classify frozen pork based on the analyzed parameters; however, a shelf life of 90days was suggested for the frozen cuts based on lipid oxidation.

Chemical compounds studied in this article: Spermidine (PubChem CID: 9539) Spermine (PubChem CID: 9384) Putrescine (PubChem CID: 9532) Cadaverine (PubChem CID: 80282) Tyramine (PubChem CID: 66449) Tryptamine (PubChem CID: 67652) Phenylethylamine (PubChem CID: 9075) Agmatine (PubChem CID: 2794990) Histamine (PubChem CID: 5818) Serotonin (PubChem CID: 160436) a b s t r a c tThe profile and levels of ten bioactive amines in fresh beef liver was determined and associated with physico-chemical parameters of quality. Furthermore, the influence of refrigerated storage at 0 ± 1 C and 7 ± 1 C and of pan-roasting on beef liver quality and safety was investigated. Fresh beef liver was characterized by pH of 6.71e6.92, TVB-N of 98.58e154.72 mg N/100 g and negative H 2 S. It contained high levels of spermine (up to 119 mg/kg), and low levels of spermidine, putrescine, tyramine and histamine. Therefore, beef liver constitutes one of the richest dietary source of spermine. During refrigerated storage, there were significant physico-chemical changes: the pH decreased, TVB-N increased, and hydrogen sulfide was moderate. The levels of most of the naturally occurring amines increased at rates which were faster at higher storage temperature. Two amines which were not initially detected, reached detectable levels e tryptamine and cadaverine. The proposed bioactive amines based indices of quality to access liver quality were not appropriate to follow gradual quality changes. A shelf life of up to 6 and 4 days during storage at 0 ± 1 C and 7 ± 1 C, respectively, is recommended. During pan-roasting at 180 C for 10 min, the levels of the polyamines increased significantly.