Polyphenolic compounds in apple (Malus domestica Borkh.) cultivars grown in Estonia

Several studies have shown that apples (Malus domestica Borkh.) in the daily diet are healthy due to their rich content of phytochemicals. The aim of this study was to compare the content of polyphenols in the peels, flesh, seeds and leaves of five apple cultivars ('Antonovka', 'angstrom kero', 'Cortland', 'Karksi renett' and 'Krista') grown in Estonia. Of the 21 collected cultivars, these five were selected on the basis of their rich or distinct chemical composition according to the LC-DAD-MS/MS data. In addition, the weight of the fruit, the number of seeds in the fruit and the weight of the seeds were determined. A total of 33 compounds were detected in the peels, 23 in the flesh, 11 in the seeds, and 25 in the leaves. They belong to four groups: 1) flavon-3-ols (quercetin and its derivatives), 2) dihydrochalcones (phloretin and its derivatives), 3) flavan-3-ols (catechin, epicatechin and oligomers), and 4) esters formed between caffeic acid and L-quinic acid (chlorogenic acid). Based on the data presented in this article, the leaves contained the highest measured total polyphenol content (TPGA). The peels contained high amounts of all the major polyphenolic groups mentioned. The apple flesh lacked flavon-3-ols and the seeds flavon-3-ols and flavan-3-ols. In the peels, the major polyphenols were quercetin galactoside (3-342 mg/100 g), procyanidin B1 (18-179 mg/100 g), and (epi)catechin trimer (28-200 mg/100 g); in the flesh chlorogenic acid (77-298 mg/100 g); in the seeds phloridzin (466 mg/100 g in 'Cortland'); and in the leaves chlorogenic acid (147-446 mg/100 g) and quercetin glycosides, especially quercetin rhamnoside (242-350 mg/100 g), quercetin galactoside (39- 334 mg/100 g) and quercetin glucoside (91-321 mg/100 g).Peer reviewe

Lipid oxidation inhibition capacity of plant extracts and powders in a processed meat model system

A meat model system was used for screening lipid oxidation inhibiting capacity of diverse horticultural plant materials. In the model, heme-containing sarcoplasmic proteins from the meat water-phase were homogenized with linoleic acid and thiobarbituric reactive substances (TBARS) were measured. 23 Plant materials were investigated at three high (50, 100, and 200 ppm) concentrations and five plant extracts were tested at three low (5, 10, and 20 ppm) concentrations over time. In the high concentration sets, summer savory freeze-dried powder, beetroot leaves extracted with 50% ethanol, and an olive polyphenol powder extracted from wastewater, inhibited oxidation the most effectively. After two weeks and at 200 ppm concentration, oxidation was reduced to 17.2%, 16.6% and 13.5% of the blank sample with no added antioxidants respectively. In the low concentration set, spray dried rhubarb juice inhibited oxidation the most after two weeks at 5 ppm where oxidation was reduced to 68.3% of the blank sample with no added antioxidants