Optimization of simultaneous flavanol, phenolic acid, and anthocyanin extraction from grapes using an experimental design: application to the characterization of champagne grape varieties.

Optimization of polyphenol extraction from grape skin, seed, and pulp was performed on Vitis vinifera L. cv. Pinot Noir, by response surface methodology using a Doehlert design. An acidified mixture of acetone/water/methanol was the best solvent for simultaneous extraction of major polyphenol groups from all berry parts, while optimum extraction times and solid-to-liquid ratios varied according to the part. The determined composition from the model agreed with independent experimental results. Analysis of the three Champagne grape varieties showed that proanthocyanidins were the major phenolic compounds in each part (60-93%). The total berry proanthocyanidin content was highest in Pinot Meunier (11 g kg(-1)) and lowest in Chardonnay (5 g kg(-1)), but Pinot Meunier pulp contained lower amounts of proanthocyanidins and phenolic acids (210 and 127 mg kg(-1) berry, respectively) than that of the other two varieties. The berry anthocyanin content was equivalent in both Pinot Noir and Pinot Meunier (632 and 602 mg kg(-1), respectively).

Enzymatic degradation of cell wall polysaccharides from mango (Mangifera indica L.) puree.

Ripe mango puree (Smith cultivar) was treated with fungal polysaccharidases containing pectinolytic, hemicellulolytic, and cellulolytic activities for 2 h at 50 degrees C. A loss of 30% of the cell wall material (CWM) was measured. CWM polysaccharides were hydrolyzed to varying degrees: 88, 65, and 65% of, respectively, galacturonic acid-, arabinose-, and rhamnose-containing polymers were hydrolyzed, whereas 50% of cellulose was degraded. After 30 min of treatment, the ethanol precipitation test on the serum was negative, indicating that pectic substances were rapidly hydrolyzed. Oligogalacturonic acids (degree of polymerization, 1-12) were observed in the serum. A viscosity drop of 90% was measured after 2 h, confirming the dominant role of pectic substances in puree viscosity.

Free volatile components of passion fruit puree obtained by flash vacuum-expansion.

Purple passion fruits were processed by the flash vacuum-expansion process. Volatile components were analyzed in purees from steam-heated fruits, steam-heated then vacuum-expanded fruits and their aromatic liquors, and fruit rind, in comparison with a reference single-strength juice. After steam heating, the puree was enriched in esters arising from the rind. Steam-heated then vacuum-expanded fruits yielded a puree impoverished in volatiles due to evaporation of approximately 10% of water. These volatile compounds were mostly recovered in aromatic liquors.