Renata Dias de Mello Castanho AMBONI***. Cleide Rosana Vieira BATISTA*** ..... 2.0AMERICAN PUBLIC HEATH ASSOCIATION. Compendium of methods for ...
Alim. Nutr., Araraquara v.18, n.2, p. 121-126, abr./jun. 2007
ISSN 0103-4235
CHEMICAL, MICROBIOLOGICAL AND SENSORY CHANGES OF MARINADE MUSSEL (PERNA PERNA, LINNÉ 1758) STORAGE AT 4ºC Mariana AVEIRO* Queli Carine PELLIZZARO** Renata Dias de Mello Castanho AMBONI*** Cleide Rosana Vieira BATISTA*** Luiz Henrique BEIRÃO*** Pedro Luiz Manique BARRETO ***
ABSTRACT: This study was carried out to evaluate the physical-chemical, microbiological and sensory attributes of the brown mussel (Perna perna) marinated with two different sauces. Microbiological, chemical and sensory changes were monitored, at 4ºC (±1ºC), for a period of 50 days. At the end of this period of storage, in both preparations, the total volatile basic nitrogen (TVB-N) remained lower than the upper limit (35 mg TVB-N per 100 g fish flesh) and pH and acidity were insignificant. On the basis of sensory analyses, the mussels marinated in the two sauces remained stable during cold storage for 42 and 21 days, respectively. KEYWORDS: Mussel; marinade; quality control; preservation; sensory attributes.
INTRODUCTION The terms marinade or marinated fish refer to fish products consisting of fresh, frozen, or salted fish or portions of fish treated with an edible organic acid and salt and then steeped in a savory sauce or oil.21 The word "marinade" is originally French and comes from the Latin for "marine"; indeed in Italian, Spanish and French it refers to soaking/ pickling in brine. What is meant by marinating today varies a great deal between countries: thus, salting, adding phosphate and some spices is sometimes considered as marinating.7 Marinades are semi-preserves; the preserving principal is the combination of acetic acid and salt, whose combined effects inhibit the action of bacteria and enzymes. The aim of marination is not only to prevent microbial growth, but also to tenderize or change the taste, texture and
structural properties of fish or meat, resulting in a product with a characteristic flavour and an extended but limited shelf life.1,9,12,13,16,17,22 The (tropical Atlantic) brown mussel, Perna perna, belongs to the Mytilidae family is a very popular edible bivalve mollusk farmed in Brazil.24 Presently, Santa Catarina State produces 11,365 tons of mussels annually, of which more than 95% are farmed in Palhoça, Governador Celso Ramos, Bombinhas, Penha and Florianópolis.11 Generally, mussels are marketed fresh in their shells, with a shelf-life not exceeding 6-7 days under refrigeration. There is thus a great need for the development of new and efficient preserving techniques, considering that mussels, like many marine products, are extremely perishable compared to other fresh meat commodities. Since there is little published information about the production of marinated Perna perna, the purpose of this study was to formulate a mussel marinade and to evaluate the physical, chemical, microbiological and sensory changes of the mussel Perna perna, marinated in this formulation, during storage at a refrigerated temperature of 4oC.
MATERIALS AND METHODS Raw Material Aquaculture mussels (Perna perna), of commercial size, were obtained from the coast of Santa Catarina, Brazil. After harvesting, the mussels were thoroughly washed in running water to remove crust and mud. They were immediately transported to the laboratory within 30 min of
* Pós-graduation in Nutrition - Center of Agricultural Science - Federal University of Santa Catarina (UFSC ) - 88034-001 - Florianópolis - SC Brazil. ** Graduation em Pharmacy - Food Tecnology - Center of Agricultural Science - Federal University of Santa Catarina (UFSC ) - 88034-001 Florianópolis - SC - Brazil. *** Department of Food Science and Technology - Center of Agricultural Science - Federal University of Santa Catarina (UFSC ) - 88034-001 Florianópolis - SC - Brazil.
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harvesting, in polystyrene boxes with crushed ice. Upon arrival the mussels were subsequently inspected and dead animals were discarded. Marination The live mussels were rapidly washed and, to make the flesh separate more easily, the shells were scalded with steam until they began to open. The mussels were then removed from their shells, rinsed in cold water (4 ± 1ºC) and soaked in 0.5% lactic acid and 5% sodium chloride solution at 4oC for 12 hours. After draining, the mussels were divided into two batches, which were marinated as follows. The first batch was immersed in a pre-chilled (4ºC) sauce containing 4.5% acetic acid (v/v), salt (NaCl), soy oil, sorbic acid (maximum 0.1 g/100 g), spices, onion and green pepper (sample A), while the second batch was marinated in the same mixture, with the addition of mustard (sample B). The mussel to liquor ratio was 1:5. Marinated mussels from each treatment were packaged in polypropylene boxes, labeled, and stored at 4 ± 1 ºC for 50 days. After 0, 7, 21, 42, and 50 days, randomly chosen mussels of each batch were removed for analysis. Analyses were conducted in triplicate or duplicate, and all reagents were of analytical grade. Microbiological Analysis The marinaded mussel samples were analyzed for the presence of salmonellae and viable counts were made of coliforms growing at 45ºC, coagulase-positive staphylococci, yeasts, molds, sulphite-reducing clostridia and psychrotrophs.2 In order to evaluate the microbiological quality of the marinade, it was tested for all of these microorganisms on the first day of the process. After that, only molds, yeasts and psychrotrophs were monitored each 10 days until the end of the experiment (50 days). Marinade samples of 25 g were homogenized with 225 mL of buffered peptone water and undiluted and diluted samples were analyzed according to the APHA method (2005), with modifications.3 Total psychrotrophs were counted after incubation at 7ºC for 10 days on plate count agar (PCA). The molds and yeasts were counted after incubation at 25ºC for 5 days on acidified potato dextrose agar (PDA). Coliforms growing at 45ºC were estimated by the most probable number technique (MPN), after culturing serial dilutions in lauryl sulfate tryptose broth (LST), incubated at 35ºC for 24 h, and E. coli broth (EC), incubated at 45.5 C for 48 h in a water bath. Coagulase-positive staphylococci were counted on Baird-Parker agar (BP), incubated at 35ºC for 48 h, following the catalase and coagulase tests. To enumerate sulfite-reducing clostridia, tryptonesulfite-cycloserine agar (TSC) was used as the selective medium, incubated at 36 ± 1ºC for 18-20 h in anaerobic (Gas-Pak) jars with an atmosphere of N2 and H2. Salmonellae were detected after enrichment in tetrathionate broth (TTB) and Rappaport-Vassiliadis broth (RP), 122
incubated respectively at 35oC and 42oC for 24 h. The selective enrichment cultures were seeded on to Hektoen enteric (HE), Salmonella-Shigella (SS) and xylose lysine deoxycholate (XLD) agars and incubated at 35oC for 24 hours. Typical Salmonella spp. colonies were subjected to biochemical screening, on triple sugar iron agar (TSI), lysine iron agar (LIA) and urea agar (UA), and to serological and other biochemical tests (dulcitol, indole, malonate, MRVP - methyl red Voges-Proskauer - and citrate). Physical and Chemical Analysis The chemical composition of marinated mussels was determined as crude protein (N x 6.25), fat, total ash, moisture, and crude fiber contents, using the methods of AOAC International.5 The total carbohydrate was calculated by difference as 100% - (% moisture + % ash + % lipid + % protein). Energy values (kcal) were calculated by multiplying each gram of protein, lipid and carbohydrate by the factors, 4, 9 and 4 respectively.25 The pH was recorded using a pH meter (Digimed, DM-20, Campinas, Brazil), the glass electrode being introduced into a mixture of homogenized sample and distilled water (1:10). Acidity was determined as stipulated by AOAC International.4 Total volatile basic nitrogen (TVB-N, mg N/100g) values were determined by the method of Gökoglu et al.13 with modifications: 10 g sample was washed into a distillation flask and 2 g magnesium oxide and a drop or two of antifoam solution were added. Samples were boiled and distilled into 50 mL of boric acid solution with an acid-base indicator in a 500 mL conical flask. After the distillation, the contents of the conical flask were titrated against 0.01 N aqueous NaOH. Sensory Analysis The sensory attributes of marinated mussel were evaluated by a panel of 13 experienced judges on each day of sampling and the results were analyzed as described by Manousaridis et al.19 Mussel marinades were served to the panelists to evaluate their appearance, flavor, texture and odor on a scale of 1 to 9, 9 being equivalent to a fresh sea mussel of top quality and 7 indicating acceptable borderline freshness, as proposed by Chang, et al.10 Statistical Analysis The physical, chemical and sensory analyses were tested statistically with the Origin 7.5 (2003) program.
RESULTS AND DISCUSSION Microbiological Analysis All marinated mussel samples were negative for Salmonella and coagulase-positive Staphylococcus. The coliform count at 45ºC was
