Irena Perucka

Extraction and determination of capsaicinoids in fruit of hot pepper Capsicum annuum L. by spectrophotometry and high-performance liquid chromatography.

The simple spectrophotometric method of determination of capsaicinoids in fresh fruit of hot pepper and the HPLC method were compared. Capsaicinoids were extracted from hot pepper fruit with the petroleum ether:acetone mixture, and then separated using thin layer chromatography on silica gel and evaluated quantitatively using the HPLC method and spectrophotometrically. The high correlation factor obtained for these methods (0.93) proved that either method can be used for determining the total of capsaicinoids in fresh and powdered hot pepper fruits isolated by the TLC method and that both can be successfully used in laboratories that are not so well equipped.

Isolation and structure elucidation of flavonoid and phenolic acid glycosides from pericarp of hot pepper fruit Capsicum annuum L.

Hot pepper fruits (Capsicum annuum L.) var. Bronowicka Ostra have been studied with regard to content of flavonoids and other phenolics. Nine compounds were isolated from pericarp of pepper fruits by preparative HPLC. Their structures were identified by chromatographic (analytical HPLC) and spectroscopic (UV, NMR) techniques. Two of the identified compounds, trans-p-ferulylalcohol-4-O-(6-(2-methyl-3-hydroxypropionyl) glucopyranoside and luteolin-7-O-(2-apiofuranosyl-4-glucopyranosyl-6-malonyl)-glucopyranoside were found for the first time in the plant kingdom. Additionally compounds: trans-p-feruloyl-beta-D-glucopyranoside, trans-p-sinapoyl-beta- D-glucopyranoside, quercetin 3-O-alpha-L-rhamnopyranoside-7-O-beta-D-glucopyranoside, luteolin 6-C-beta-D-glucopyranoside-8-C-alpha-L-arabinopyranoside, apigenin 6-C-beta-D-glucopyranoside-8-C-alpha-L-arabinopyranoside and luteolin 7-O-[2-(beta-D-apiofuranosyl)-beta-D-glucopyranoside] were found for the first time in pepper fruit Capsicum annuum L.

Phenylalanine ammonia-lyase and antioxidant activities of lipophilic fraction of fresh pepper fruits Capsicum annum L.

Capsaicin and dihydrocapsaicin content, their antioxidant activity, the activity of the fraction containing flavonoids, as well as the activity of l-phenylalanine ammonia-lyase (PAL) were studied in the fruit of the hot pepper Capsicum annuum L., var. Cyklon and Bronowicka Ostra. For analyses, pericarps of fruit at two stages were used: before the beginning of maturation — green; and mature — red. The fruit of the cv. Bronowicka Ostra was characterized by a higher PAL activity, capsaicinoid level and higher antioxidant activity than that found in Cyklon. It was found that red fruit of both cultivars had higher antioxidant activity in the capsaicinoid and flavonoid fractions. The PAL activity was as much higher in the red than in the green (unripe) fruits. The antioxidant activity under the same experimental conditions was similar in both capsaicinoid and flavonoid fractions of cv. Bronowicka Ostra.

Ozone-induced changes in the content of bioactive compounds and enzyme activity during storage of pepper fruits.

This paper presents for the first time the results of investigations concerning the effect of treatment of whole pepper fruits with gaseous ozone and the refrigeration storage period conditions on pepper quality. The effects are reflected in changes in the flavonoid contents, the antioxidant activity of the phenolic compound fraction and the enzymes involved in phenylpropanoid metabolism. The investigations were carried out on a hot pepper fruit cultivar, Cyklon. It was found that the levels of a majority of flavonoids, in particular those of quercetin 3-O-rhamnoside and quercetin 3-O-rhamnoside-7-O-glucoside increased in the pericarp of fruits treated with ozone for 3h and stored for 20days (by 25% relative to the control). Simultaneously, reduced phenylalanine ammonia-lyase and tyrosine ammonia-lyase activity were noted, which implies slight degradation of enzymes caused by the ozone treatment and enhancement of the polyphenol oxidase and guaiacol oxidase activity involved in response to increased oxidative stress.