Composition of Phenolic Compounds in a Portuguese Pear (Pyrus communis L. Var. S. Bartolomeu) and Changes after Sun-Drying

Abstract

The composition of phenolic compounds of a Portuguese pear cultivar (Pyrus communis L. var. S. Bartolomeu) was determined by HPLC after thioacidolysis. The average concentration of phenolic compounds in pear harvested at commercial maturity stage was 3.7 g per kg of fresh pulp. Procyanidins were the predominant phenolics (96%), with a mean degree of polymerization (mDP) of 13-44; hydroxycinnamic acids (2%), arbutin (0.8%), and catechins (0.7%) were also present. The most abundant monomer in the procyanidin structures was (-)-epicatechin (99%), which was found as extension and terminal units; (+)-catechin (1%) was found only as a terminal unit. Sun-drying of these pears caused a decrease of 64% (on a dry pulp basis) in the total amount of native phenolic compounds. Hydroxycinnamic acids and procyanidins showed the largest decrease; the B2 procyanidin was not found at all in the sun-dried pear. Less affected were arbutin and catechins. In the sun-dried pear, the procyanidins with high mDP became unextractable in the solvents used.

Water at room temperature as a solvent for the extraction of apple pomace phenolic compounds

“…The extraction of phenolic compounds was performed by a fractionation method based on a method previously described (Ferreira et al, 2002). This method was modified according to the nature of the sample and the aim of the study.…”

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

“…The following list presents the food sources of phenolic acids and the papers in which they were discussed: Apples and apple juice [16, 39 -41], cherries [23, 42 -44], pears [45,46], must and wine [17, 20, 47 -54], sherry vinegar [55], sherry wine [56], winemaking waste solids [57], blueberries and blueberry juice [14, 58 -62], raspberries [4], strawberries [63,64], bayberries (Myrica rubra) [65], orange peel [66], mangos [67], passion fruit juice [68], dates [69], broccoli [70,71], lettuce [3], tomatoes [72 -74], potatoes [75,76], jicama [77], carrots [78], asparagus [79,80], leavy vegetables [81], legumes [22,53,82], olives and olive oil [83 -85], rye [86], oat [87], sorghum [88], wheat bran [89,90], cereal brans [91], barley [92], rice [93], sesame [94], sea buckthorn [95], mustard seeds [96], coffee beans [97], soybeans [98,…”

“…The following aspects are mentioned in the papers: Storage under different conditions [3, 14, 16, 20, 23, 40, 41 -43, 46, 49, 53, 63, 67, 68, 70, 74, 75, 77 -80, 83, 91, 100, 102], washing treatment [78,104], blanching [59,65,101], drying [102], sun-drying [37,45], treatment with a growth regulator [23,41], alkaline and acid hydrolysis [90], juice centrifugation [65], flash release process [54], cowinemaking and wine aging [52,56,105], grape destemming [17], fermentation [44,57], germination [22,82,93], extraction [60,84,85,89], thermal stability [44], bread making [86], cooking [22], roasting [97], stir-baked processing [96], steaming [87], thermal treatment [50,58,68,81], SO 2 treatment [106], break-process [72], freezing [4,71], freeze-drying [64], maceration [47,48,51], enzymatic treatment …”

“…The [175,214], acidification [223], 1-methylcyclopropene (MCP) treatment [41], drying [45,101,213,225], sensory effects [232,233], brewing [131,215], cooking and steaming [33], stress treatment [224], browningblanching and PPO activity [101], and provenience [138].…”

Understanding the Characteristics of Oleuropein for Table Olive Processing

“…For this reason the nutritional intake of oleuropein is usually considered as questionable [1,2]. Although the majority of the polyphenols found in table olives are derivatives of its hydrolysis, in most cases, the concentration of oleuropein in edible sources like table olives and olive oil has been found to be very low [3].…”