Stability Kinetics of Anthocyanins of Grumixama Berries (Eugenia brasiliensis Lam.) during Thermal and Light Treatments.

Grumixama (Eugenia brasiliensis Lam.) are red-colored fruits due to the presence of anthocyanins. In this paper, anthocyanin-rich extracts from grumixama were submitted to different temperatures and light irradiations, with the aim of investigating their stabilities. The thermal stability data indicated that a temperature range from 60 to 80 °C was critical to the stability of the anthocyanins of the grumixama extracts, with a temperature quotient value (Q10) of 2.8 and activation energy (Ea) of 52.7 kJ/mol. The anthocyanin-rich extracts of grumixama fruits showed the highest stability during exposure to incandescent irradiation (50 W), followed by fluorescent radiation (10 W). The t1/2 and k were 59.6 h and 0.012 h-1 for incandescent light, and 45.6 h and 0.015 h-1 for fluorescent light. In turn, UV irradiation (25 W) quickly degraded the anthocyanins (t1/2 = 0.18 h and k = 3.74 h-1). Therefore, grumixama fruits, and their derived products, should be handled carefully to avoid high temperature (>50 °C) and UV light exposure in order to protect the anthocyanins from degradation. Furthermore, grumixama fruits showed high contents of anthocyanins that can be explored as natural dyes; for example, by food, pharmaceutical and cosmetic industries. In addition, the results of this study may contribute to the setting of processing conditions and storage conditions for grumixama-derived fruit products.

Total and Free Hydrogen Cyanide Content and Profile of Bioactive Amines in Commercial Tucupi, a Traditionally Derived Cassava Product Widely Consumed in Northern Brazil.

Tucupi is a broth derived from cassava roots which is produced after the spontaneous fermentation of manipueira (the liquid portion obtained by pressing cassava roots), followed by cooking. This product is widely consumed along with traditional dishes in the Brazilian Amazonia and is already used in different places worldwide. In this study, tucupi obtained from the markets of Belém (Pará, Brazil) and produced using agroindustrial (11 samples) and non-agroindustrial (11 samples) units were investigated to determine their physicochemical characteristics, total and free HCN contents, and free bioactive amine profiles. Most of the samples showed significant variations (p ≤ 0.05) in pH (2.82-4.67), total acidity (0.14-1.36 g lactic acid/100 mL), reducing sugars (up to 2.33 g/100 mL), and total sugars (up to 4.35 g/100 mL). Regarding the amines, four biogenic amines (0.5-4.2 mg/L tyramine, 1.0-23.1 mg/L putrescine, 0.5-66.8 mg/L histamine, and 0.6-2.9 mg/L tryptamine) and one polyamine (0.4-1.7 mg/L spermidine) were identified in the tucupi samples. Even in the tucupi produced using the agroindustrial units, which had quality seals provided by the local regulatory agency, high levels of biogenic amines (4.4-78.2 mg/L) were observed, as well as high dosages of total (8.87-114.66 mg/L) and free (0.80-38.38 mg/L) HCN. These facts highlight the need for better knowledge regarding the product manufacturing process to establish standardization and high-quality conditions for tucupi processing since high contents of biogenic amines and HCN are commonly associated with adverse health effects.

Chemical composition of different muscle zones in pirarucu (Arapaima gigas)

Abstract Identifying potential patterns in pirarucu (Arapaima gigas) composition, as a function of the different fish muscle zones (dorse, venter, ventrecha and tail), was the main objective of this research. For such, the different pirarucu muscle zones were evaluated, in order to obtain proximate composition and minerals content. It was also determined amino acids and fatty acids contents in fish muscle. The dorsal, ventral and tail muscle zones presented similar moisture (76.5-78.2%), protein (17.8-18.9%), total lipids (1.0-1.5%) and ash (0.9-1.2%) contents. On the other hand, the ventrecha zone presented 25.8% of protein and the major total lipids content (17.1%). The main minerals found in fish muscle were K (183.5-288.6 mg/100 g muscle) and Na (65.1-175.5 mg/100 g). Glutamic acid (3027.6 mg/100 g muscle) was the main amino acid found in fish muscle, which presented 48% of essential amino acids in the protein fraction. Lipids content showed 57.3% of unsaturated fatty acids and 42.7% of saturated fatty acids.

Combined osmotic dehydration and drying process of pirarucu (Arapaima gigas) fillets.

The osmotic dehydration (OD) and complementary drying of pirarucu (Arapaima gigas) fillets were studied. Pieces of the dorsal portion of pirarucu (60 mm × 20 mm × 10 mm) underwent OD in a binary solution (NaCl-water) with the application of vacuum pulse following a central rotatable composite design. The effect of the following process variables was assessed: temperature (20-40 °C), osmotic solution concentration (15-25% NaCl), and vacuum pulse pressure (7-101 kPa) on water loss (WL), solid gain (SG), and water activity (aw). OD kinetics was obtained and the Peleg model was fitted to WL and SG data. The osmotically dehydrated pirarucu was dried (40-70 °C) in a fixed-bed dryer and mathematical models were fitted to the drying data. The optimal operational condition for the OD process was 35 °C, solution with 25% NaCl, and atmospheric pressure, which yielded WL of 14.87 ± 1.46%, SG of 8.56 ± 0.45%, and aw of 0.87 ± 0.02. The Peleg model efficiently predicted the WL and SG kinetics. The increase in the water loss in drying was more evident at low temperatures (40-50 °C) with effective diffusivity ranging from 10.85 × 10-9 to 12.30 × 10-9 m2/s. The Midilli and Page models efficiently predicted the drying kinetics.