Análisis del contenido de ácidos grasos y estimación de índices de calidad nutricional en conservas de atún

RESUMEN Los alimentos de origen marino se caracterizan en general por su alto contenido en ácidos eicosapentaenoico (EPA) y docosahexaenoico (DHA), dos ácidos grasos poliinsaturados de la familia n-3 con funciones esenciales en el organismo humano. En Chile, las conservas de pescado, entre ellas el atún enlatado, son una de las formas principales de consumo de alimentos del mar. En este trabajo se analizaron los perfiles de ácidos grasos y se estimaron varios índices de calidad nutricional de distintas conservas de lomos de atún en agua y en aceite vegetal disponibles en supermercados de Santiago de Chile. Las cantidades de EPA+DHA encontradas oscilaron entre 184 y 310 mg/100 g y entre 110 y 336 mg/100 g en las conservas de atún en agua y en aceite, respectivamente. El ácido graso más abundante en las conservas de atún en agua fue el DHA, mientras que en las conservas en aceite fue el ácido linoleico, perteneciente a la familia n-6. Los índices de calidad lipídica del pescado (FLQ) y aterogénico (IA) fueron más altos en las conservas de atún en agua que en las de atún en aceite, mientras que la relación ácidos grasos hipocolesterolémicos/hipercolesterolémicos (HH) presentó valores mayores en el atún enlatado en aceite. El índice trombogénico (IT) fue en general más alto en las conservas de atún en aceite.

ABSTRACT Foods from marine origin are known to have a high content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two polyunsaturated fatty acids from the n-3 family with essential roles in the human organism. Canned fish, including tuna, is one of the main formats to consume marine foods in Chile. In this work, samples of canned tuna in water and in oil available in supermarkets of Santiago de Chile were analysed to elucidate their fatty acid composition and to estimate several indexes of nutritional quality related to the lipid fraction of such foods. The amounts of EPA+DHA ranged between 184 and 310 mg/100 g and between 110 and 336 mg/100 g for canned tuna in water and oil, respectively. DHA was the most abundant fatty acid in canned tuna in water, whereas linolenic acid (an n-6 fatty acid) was found to be the most abundant in canned tuna in oil. The Fish Lipid Quality (FLQ) and atherogenic index (AI) reached higher values in canned tuna in water than in canned tuna in oil, whereas the ratio hypocholesterolemic/hypercholesterolemic fatty acids (HH) was higher in canned tuna in oil. The thrombogenic index (TI) was generally higher for canned tuna in oil.

Detection of Parvalbumin Fish Allergen in Canned Tuna by Real-Time PCR Driven by Tuna Species and Can-Filling Medium.

Canned tuna is considered one of the most popular and most commonly consumed products in the seafood market, globally. However, in past decades, fish allergens have been detected as the main concern regarding food safety in these seafood products and are listed as the top eight food allergies. In the group of fish allergens, parvalbumin is the most common. As a thermally stable and calcium-binding protein, parvalbumin can be easily altered with changing the food matrices. This study investigated the effect of a can-filling medium (tomato sauce, spices, and brine solutions) on the parvalbumin levels in canned tuna. The effect of pH, calcium content, and the DNA quality of canned tuna was also investigated before the parvalbumin-specific encoded gene amplification. The presence of fish allergens was determined by melting curve analyses and confirmed by agarose gel electrophoresis. The obtained results showed that the presence of parvalbumin in commercially canned tuna was driven by can-filling mediums, thermal conductivity, calcium content, and the acidity of various ingredients in food matrices. The intra-specific differences revealed a variation in fish allergens that are caused by cryptic species. This study proved that allergens encoding gene analyses by agarose electrophoresis could be used as a reliable approach for other food-borne allergens in complex food matrices.

Oxidative Stability and Antioxidant Activity in Canned Eels: Effect of Processing and Filling Medium.

The effect of canning and the use of different filling media (sunflower oil, olive oil, and spiced olive oil) on oxidation parameters (acidity, peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) index), antioxidant capacity, and total phenol and vitamin E contents in eels was studied. A preliminary frying treatment caused a decrease in titratable acidity and an increase in TBARS, antioxidant capacity, and vitamin E in the eel muscle. During sterilization, TBARS also increased significantly. The magnitude of the changes depended on the filling medium. Storage also had a significant effect on oxidation parameters in eel muscle and in filling media. After one year of storage, the sunflower oil and canned eels packed in this oil presented higher antioxidant capacity and vitamin E content than olive oil, spiced olive oil, or canned eels packed in these oils. However, the total phenol contents were higher when olive oil or spiced olive oil were used as filling media. Despite the losses, the results show that the canning process and subsequent storage preserved a great part of the antioxidant capacity and vitamin E content of the filling medium, which is of interest to the consumer. Both sunflower oil and olive oil as filling media are of great nutritional interest.

Free Amino Acids and Biogenic Amines in Canned European Eels: Influence of Processing Step, Filling Medium and Storage Time.

This study evaluated the effects of the canning process and different filling media on the free amino acid and biogenic amine contents of eels. The main free amino acids were histidine, taurine and arginine, which constituted 72% of the free amino acids in raw eels. All steps in the canning process significantly altered the free amino acid content of eels, relative to raw samples. The changes were influenced by the step, the composition of the frying or filling medium and the storage time. The biogenic amine contents were very low in all samples. Histamine was not detected in either raw eels or canned eels. The highest values were obtained for 2-phenylethylamine. The step of the canning process, the composition of the frying or filling medium and storage time also determined the changes in the biogenic amine contents. The biogenic amines indices were low, indicating the good quality of canned eels.

Fatty acid profiles and lipid quality indices in canned European eels: Effects of processing steps, filling medium and storage.

This study evaluated the effects of the canning process, the filling medium (sunflower or olive oil), the spices included as ingredients and storage on the fatty acid profiles and related lipid quality indices in the European eel. The fatty acids did not undergo any changes during thawing-salting, because of the short salting periods. However, frying, sterilization and room storage greatly altered the fatty acid profiles. In general, the nutritional value and the lipid quality increased, owing to absorption of the oil used in the canning process. The fatty acid profiles of canned eels tended to be similar to those of the filling medium. Significant differences (p < 0.05) between eels canned in sunflower oil, olive oil and spiced olive oil were observed in relation to some fatty acids. The lipid profiles of the canned eels indicated the high nutritional quality of the product.

Principal Component Analysis of Time-Related Changes of Some Essential Mineral Contents of Canned Silver Carp (Hypophthalmichthys molitrix) in Different Filling Media.

The kinetic reaction for changes in some essential mineral contents (iron, zinc, calcium, sodium, and copper) of silver carp canned in sunflower oil, soybean oil, olive oil, and brine as filling media was assessed after a short- (1 year) and long-term storage (3, 5, and 7 years). The mineral nutrition value of cans was also determined to take into account the changes in estimated daily intake (EDI) of elements during storage and then clustered by principal component analysis (PCA). Results revealed that the reduction of trace elements in brine was higher than in other filling media due to formation of insoluble metal hydroxide. No changes were detected in the mineral content of cans after 1-year storage in comparison to fresh cans, while the content and daily intake of zinc, iron, calcium, copper, and sodium were significantly decreased in all filling media after 3, 5, and 7 years of storage. The first-order reaction model was detected for reduction of mineral contents in filling medium. Post-storage daily intake of iron, sodium, calcium, zinc, and copper was 0.06 up to 0.18, 1.9 up to 9.7, 1.8 up to 9.1, 0.02 up to 0.10, and 0.004 up to 0.02 mg/day/person, respectively. Filling medium had significant effects on estimated daily intake of zinc, sodium, calcium, and copper in long-term sorted cans. PC1 and PC2 explained 93.7% of the total variance of the dataset, contributing 68.7 and 20.5%, respectively.