Influence of time-temperature in the antioxidant activity, anthocyanin and polyphenols profile, and color of Ardisia compressa K. extracts, with the addition of sucrose or citric acid.

The objective of this study was to analyze and optimize the influence of heating time and citric acid (CA) or sucrose addition of Ardisia compressa K. extracts on phenolic compounds (TPC), monomeric anthocyanins (MAA), antioxidant activity (TAC), color density (CD), and hue tint (HT), using a full factorial design. Extractions were performed: temperature (25, 50, or 70 °C), time (15, 30, 60, or 90 min), CA (0.0 or 0.02 g), and sucrose (0.0 or 5.0 g). HPLC-DAD-ESI-MS was conducted in extracts without additives and with the addition of CA (0.02 g) or sucrose (5.0 g), at 25, 50, or 70 °C for 15 min. CA-added extracts showed maximum TPC, MAA, TAC (DDPH and ABTS assays), and CD values, with the lowest HT values. Malvidin 3-O-galactoside and myricetin-O-hexoside were the predominant anthocyanin and non-anthocyanin polyphenols. Time, temperature, and solute influenced the optimized extraction of TPC, MAA, anthocyanins, TAC, CD, and HT.

Phytochemical, sensory attributes and aroma stability of dense phase carbon dioxide processed Hibiscus sabdariffa beverage during storage.

The effect of dense phase carbon dioxide (DPCD) processing (34.5 MPa, 8% CO2, 6.5 min, and 40 °C) on phytochemical, sensory and aroma compounds of hibiscus beverage was compared to a conventional thermal process (HTST) (75 °C for 15 s) and a control (untreated beverage) during refrigerated storage (4 °C). The overall likeability of the hibiscus beverage for all treatments was not affected by storage up to week 5. DPCD process retained more aroma volatiles as compared to HTST. Aroma profiles in the beverages were mainly composed of alcohols and aldehydes with 1-octen-3-ol, decanal, octanal, 1-hexanol, and nonanal as the compounds with the highest relative percentage peak areas. A loss of only 9% anthocyanins was observed for the DPCD processed hibiscus beverage. Phytochemical profiles in the hibiscus beverage included caffeoylquinic acids, anthocyanins, and flavonols. No major changes in total phenolics and antioxidant capacity occurred during the 14 weeks of storage.

Effect of Brown Seaweed (Macrocystis pyrifera) Addition on Nutritional and Quality Characteristics of Yellow, Blue, and Red Maize Tortillas.

The objective of this study was to analyze the effect of incorporating Macrocystis pyrifera into yellow, blue, and red maize masa and tortillas. The nutritional composition and mineral content of tortillas was determined, and the color, texture, total phenolic compounds (TPC), and antioxidant capacity of masas and tortillas were measured. The addition of seaweed led to a significant decrease in moisture and a significant increase in ash, protein, and fiber, while no differences were observed in the lipid and carbohydrate content. There was a significant increase in all analyzed minerals (Na, Ca, P, K, and Mg). Tortillas weighed 24.54 ± 1.02 g, had a diameter of 11.00 ± 0.79 cm, and a thickness of 0.32 ± 0.09 cm. All color parameters were significantly affected by seaweed concentration. The hardness of the masas was 2.18-22.32 N, and the values of the perforation test of the tortillas were 1.40-4.55 N. The TPC of the masas and tortillas was measured in water and methanol:water extracts. Results were higher in the water extracts (1141.59-23,323.48 mg GAE/100 g masa and 838.06-2142.34 mg GAE/100 g tortilla). Antioxidant capacity (ORAC) was higher for methanol:water extracts (14,051.96-44,928.75 µmol TE/100 g masa and 14,631.47-47,327.69 µmol TE/100 g tortilla).

Enzyme release of phenolics from muscadine grape (Vitis rotundifolia Michx.) skins and seeds.

Enzyme degradation of plant cell wall polysaccharides can potentially enhance the release of bioactive phenolics. The aim of this study was to evaluate various combinations of solvent and enzyme, enzyme type (cellulase, pectinase, ß-glucosidase), and hydrolysis time (1, 4, 8, 24 h) on the release of muscadine grape skin and seed phenolics, and their antioxidant activities. Results showed that pre-treated muscadine skins and seeds with enzymes decreased total phenolic yield compared with solvent (50% ethanol) alone. Enzyme release of phenolics from skins of different muscadine varieties was significantly different while release from seeds was similar. Enzyme hydrolysis was found to shorten extraction time. Most importantly, enzyme hydrolysis modified the galloylated form of polyphenols to low molecular weight phenolics, releasing phenolic acids (especially gallic acid), and enhancing antioxidant activity.

Physicochemical and phytochemical properties of cold and hot water extraction from Hibiscus sabdariffa.

UNLABELLED: Hibiscus cold (25 °C) and hot (90 °C) water extracts were prepared in various time-temperature combinations to determine equivalent extraction conditions regarding their physicochemical and phytochemical properties. Equivalent anthocyanins concentration was obtained at 25 °C for 240 min and 90 °C for 16 min. Total phenolics were better extracted with hot water that also resulted in a higher antioxidant capacity in these extracts. Similar polyphenolic profiles were observed between fresh and dried hibiscus extracts. Hibiscus acid and 2 derivatives were found in all extracts. Hydroxybenzoic acids, caffeoylquinic acids, flavonols, and anthocyanins constituted the polyphenolic compounds identified in hibiscus extracts. Two major anthocyanins were found in both cold and hot extracts: delphynidin-3-sambubioside and cyanidin-3-sambubioside. In general, both cold and hot extractions yielded similar phytochemical properties; however, under cold extraction, color degradation was significantly lower and extraction times were 15-fold longer. PRACTICAL APPLICATION: Hibiscus beverages are prepared from fresh or dried calyces by a hot extraction and pasteurized, which can change organoleptic, nutritional, and color attributes. Nonthermal technologies such as dense phase carbon dioxide may maintain their fresh-like color, flavor, and nutrients. This research compares the physicochemical and phytochemical changes resulting from a cold and hot extraction of fresh and dried hibiscus calyces and adds to the knowledge of work done on color, quality attributes, and antioxidant capacity of unique tropical products. In addition, the research shows how these changes could lead to alternative nonthermal processes for hibiscus.