Optimization of the Ultrasound-Assisted Extraction of Phenolic Compounds from Brosimum alicastrum Leaves and the Evaluation of Their Radical-Scavenging Activity

In order to maximize the yield of the total phenolic content (TPC) and total monomeric anthocyanin (TMA) from Brosimum alicastrum leaf and to study the radical-scavenging activity, a three-level three-factor Box–Behnken design (BBD) was used to determine the optimal points for ultrasound-assisted extraction (UAE). In this study, we analyzed the extraction time (10, 20, and 30 min), temperature (28, 30, and 32 °C), and probe sonication power (40%, 28 W/cm2; 60%, 51 W/cm2; and 80%, 74 W/cm2). Analysis of variance (ANOVA) indicated that the sonication power plays a significant role in the extraction of phenolic compounds. An increase in time and temperature resulted in a decrease in the yield, in particular, of the TMA group. DPPH was found to be a better indicator of radical-scavenging activity than ABTS. The predicted TPC and TMA optimum levels (45.18 mg GAE/g and 15.16 mg CyE/100 g) were obtained at 28 °C, 80%, and 20–10 min. DPPH obtained a maximum value (67.27 μmol TE/g) under same optimization conditions. The RSM confirmed that TPC and TMA enhanced the antioxidant activity when subjected to low temperature (28 °C), extraction time less than 20 min, and higher sonication power (74 W/cm2), and hence achieving the better DPPH scavenging activity

Interactive effect of pH and temperature on antioxidant activity in the sea cucumber <i>Isostichopus badionotus</i> exposed to cold–heat thermal stress for 6 h. Left = superoxide dismutase; Center = glutathione peroxidase; Right = catalase.

<p>■ pH 8.17 ±0.02; ■ pH 7.70 ±0.08; control conditions: pH 8.17 ±0.02, 26 ±0.2°C. Columns represent mean ±SE; n = 5 with the exception of the control where n = 10 (factorial ANOVA; Tukey’s HSD, <i>P</i> < 0.05). The asterisks indicate significant differences between pH at the same temperature. Different letters (lower case for pH 8.17; capital letters for pH 7.70) represent significant differences between different temperature levels.</p

Effect of temperature on the basal activity of phenoloxidase and lysozyme from the sea cucumber <i>Isostichopus badionotus</i> exposed to two water pH values.

<p>■ pH 8.17 ±0.02; ■ pH 7.70 ±0.08; control conditions: pH 8.17 ±0.02, 26 ±0.2°C. Columns represent mean ±SE; n = 5 with the exception of the control where n = 10 (factorial ANOVA; Tukey’s HSD, <i>P</i> < 0.05). Different letters (lower case for pH 8.17; capital letters for pH 7.70) represent significant differences between temperature levels.</p

Effect of temperature on the expression of heat shock protein 70 (hsp70) from the sea cucumber <i>Isostichopus badionotus</i> exposed to two pH values.

<p>■ pH 8.17 ±0.02; ■ pH 7.70 ±0.08; control conditions: pH 8.17 ±0.02, 26 ±0.2°C. Columns represent mean ±SE; n = 5 with the exception of the control where n = 10 (factorial ANOVA; Tukey’s HSD, <i>P</i> < 0.05). Different letters (lower case for pH 8.17; capital letters for pH 7.70) represent significant differences between temperatures.</p

Expression of heat shock protein 70 (hsp70) from the sea cucumber <i>Isostichopus badionotus</i> in response to sublethal thermal tolerance.

<p>Line represents percentage survival; columns represent mean ±SE; n = 12 (factorial ANOVA; Tukey’s HSD, <i>P</i> < 0.05). Different letters represent significant differences between the exposure times.</p

Effect of pH on temperature controlled degradation of reactive oxygen species, heat shock protein expression, and mucosal immunity in the sea cucumber <i>Isostichopus badionotus</i>

<div><p>This study evaluated the effect of pH on the activity of antioxidant and immune enzymes in the sea cucumber <i>Isostichopus badionotus</i> exposed to different temperatures. The organisms (530 ±110 g) were exposed to 16, 20, 24, 28, 30, 34 and 36°C for 6 h to evaluate thermal limits at two water pH values (treatment = 7.70; control = 8.17). For the thermal tolerance experiment, the organisms were exposed to sublethal temperature of 34°C for 3, 6, 12, 24, and 48 h. <i>I</i>. <i>badionotus</i> showed signs of thermal stress by synthesizing heat shock protein 70 (hsp70) at the cold (16°C) and warm thermal limits (34°C). The glutathione peroxidase (GPx) showed a negative correlation with superoxide dismutase (SOD) activity in modulating the effect of oxidative stress at different temperature levels. Specifically, GPx activity was maximal at the extremes of the cold and warm temperatures (16, 20, and 36°C) tested, while contrarily, the SOD activity increased significantly in the narrow range of temperature between 28 and 30°C, as a part of a reaction to offset oxidative damage. The effect of pH on the expression of hsp70 was not significant, whereas the antioxidant enzymes activity was stimulated at pH 7.70. Mucosal immunity, evidenced by the activation of the phenoloxidase (PO) system, increased above the basal level at pH 7.70 and at 28, 30, and 34°C. Independent of pH, the temperature of 34°C was identified as the 12 h-sublethal upper limit for <i>I</i>. <i>badionotus</i>.</p></div

Sublethal thermal tolerance (34°C) from the sea cucumber <i>Isostichopus badionotus</i> exposed to different pH.

<p>Columns represent mean ±SE; n = 6 (factorial ANOVA; Tukey’s HSD, <i>P</i> < 0.05). ■ pH 8.17 ±0.02; ■ pH 7.70 ±0.08; control conditions: pH 8.17 ±0.02, 26 ±0.2°C. The asterisks indicate significant differences between pH values at the same temperature. Different letters (lower case for pH 8.17; capital letters for pH 7.70) represent significant differences between the exposure times at the same pH.</p

Quality indicators and shelf life of red octopus (Octopus maya) in chilling storage

Abstract There are no precedents concerning the quality of Octopus maya during chilled storage. This study evaluated the shelf life of the red octopus in chilling storage (4oC) and the correlation of the sensory quality index with microbiological counting and the biochemical indicators (hypoxanthine, histamine and volatile amines). A total of 112 whole raw octopi (average weight of 896 g) were randomly selected from seven batches and exposed to 4°C for 18, 24, 48, 72, 84, 96, and 100 h. The histamine concentration (91.7%), followed by the counts of psychrotrophic bacteria (5.5%) and hypoxanthine (2.2%), were the predictors from the redundancy analysis that better explained the changes taking place during the chilling hours. After 72 h of chilling, the microbial count was determined to be log 4.7 CFU/g, and the octopus samples were classified as B quality (minor sensory quality defects) based on the sensory quality scale. Although the samples were not classified as unacceptable at 100 h of refrigeration by the sensory index, the level of histamine reached the defect action level (5 mg/100 g) as ruled by the International Food Safety Authorities. The shelf life of the red octopus in chilling storage was predicted to be 119 h