Utjecaj skladištenja kontroliranom atmosferom na kvalitetu hrvatskih tradicionalnih sorti jabuke

The aim of this work was to investigate the influence of cold storage at 2 °C for 180 days on water content, total acids, reducing and total sugar, antioxidant activity, polyphenol oxidase activity, and polyphenol profile of three Croatian traditional apple cultivars (‘Kanadska Reneta’, ‘Ilzer Rosenapfel’, ‘Wagener’). A significant variation in polyphenol profile of apple cultivars under investigation was noted. The most represented polyphenols in all apple cultivars were procyanidin B2 followed by chlorogenic acid, epigallocatechin, epicatechin, and phloridzin. After storage, the content of procyanidin B2 and chlorogenic acid was higher, while content of epigallocatechin after storage was lower in all investigated apple cultivars. Water content before storage ranged between 79.17 and 80.76 %, and after storage between 75.62 and 78.56 %. Total acids, polyphenol oxidase activity, and flavonoids had decreased during storage, while reducing and total sugar content was higher after storage. Moreover, after storage, cultivar ‘Kanadska Reneta’ had the highest antioxidant activity measured by both ABTS and DPPH methods, 1.65 and 0.70 mmol trolox kg–1, respectively. A significant variation in polyphenol profile of apple cultivars under investigation was noted. The most represented polyphenols in all apple cultivars were procyanidin B2, followed by chlorogenic acid, epigallocatechin, epicatechin, and phloridzin. After storage, the content of procyanidin B2 and chlorogenic acid was higher, while content of epigallocatechin after storage was lower in all investigated apple cultivars. Overall, it can be concluded that investigated apple cultivars, after storage, preserved most of the antioxidants and functional properties.Cilj ovog rada bio je istražiti utjecaj skladištenja kontroliranom atmosferom na 2 °C tijekom 180 dana na polifenolni profil, sadržaj vode, ukupne kiseline, reducirajuće i ukupne šećere, antioksidacijsku aktivnost i aktivnost polifenol oksidaze triju hrvatskih tradicionalnih sorti jabuke (´Kanadska Reneta’, ‘Ilzer Rosenapfel’, ‘Wagener’). Uočena je značajna varijacija u profilu polifenola ispitivanih sorti jabuke. Najzastupljeniji polifenoli kod svih sorti jabuke bili su procijanidin B2, zatim klorogenska kiselina, epigalokatehin, epikatehin i floridzin. Nakon skladištenja sadržaj procijanidina B2 i klorogenske kiseline bio je veći, dok je sadržaj epigalokatehina nakon skladištenja bio manji kod svih ispitivanih sorti jabuke. Sadržaj vode prije skladištenja kretao se između 79,17 i 80,76 %, a nakon skladištenja između 75,62 i 78,56 %. Tijekom skladištenja došlo je do smanjenja ukupnih kiselina, aktivnosti polifenol oksidaze i udjela flavonoida, dok je sadržaj ukupnih šećera bio veći nakon skladištenja. Štoviše, sorta ‘Kanadska Reneta’ nakon skladištenja imala je najveću antioksidacijsku aktivnost mjerenu ABTS i DPPH metodom, 1,65 odnosno 0,70 mmol trolox/kg–1. Uočena je značajna varijacija u polifenolnom profilu ispitivanih sorti jabuke. Najzastupljeniji polifenoli kod svih sorti jabuke bili su procijanidin B2, zatim klorogenska kiselina, epigalokatehin, epikatehin i floridzin. Nakon skladištenja sadržaj procijanidina B2 i klorogenske kiseline bio je veći, dok je sadržaj epigalokatehina nakon skladištenja bio niži kod svih ispitivanih sorti jabuke. Sveukupno se može zaključiti da su ispitivane sorte jabuka nakon skladištenja sačuvale najveći dio antioksidativnih i funkcionalnih svojstava

Occurrence of Patulin and Polyphenol Profile of Croatian Traditional and Conventional Apple Cultivars during Storage

Apples and apple-based products are among the most consumed fruits around the world. However, they are susceptible to infection with the fungi Penicilium expansum. In addition to the reduction of apple quality, secondary metabolism of this fungus produces a mycotoxin patulin that has a negative effect on human health. Currently, there is no available research in the literature on the resistance of Croatian traditional apple cultivars to contamination with P. expansum, and consequently, on the patulin content in apples and apple juice produced from those apples. Although the mechanism of apple resistance to fungal diseases has not yet been sufficiently investigated, some studies have shown that polyphenolic compounds have some impact on fungi growth. In order to contribute with new knowledge, this research deals with monitoring the growth of P. expansum on apples, patulin detection by LC/MS-MS, determination of polyphenol profile by validated HPLC method, and determining the effect of polyphenolic compounds on fungi growth and patulin production during apple storage. The results of this study have shown that Croatian traditional apple cultivars harvested from family farm Horvatić contain higher concentration of polyphenolic compounds and higher antioxidant activity. At the same time, they showed more resistance to infection by P. expansum than conventional ones. The higher content of dihydrochalcones and flavanols encouraged the biosynthesis of patulin in examined cultivars. However, the higher content of non-flavonoids such as 2-6 dimethoxybenzoic acid, 4-hydroxycinnamic acid and chlorogenic acid leads to decrease in content of patulin. In conclusion, it seems that content of polyphenols and patulin production are correlated

Identification and Quantification of Polyphenols in Croatian Traditional Apple Varieties

Apples and apple-based products are particularly interesting due to being a good source of polyphenols in an everyday diet. Recently there has been increased interest in the preservation of traditional apple varieties due to studies that suggest that traditional apple varieties have a higher content of polyphenols and antioxidant activity compared to commercial varieties. This study shows that traditional apple varieties contain higher concentration of polyphenolic compounds than conventional ones, such as chlorogenic acid (1.29–456 mg/kg dw), catechin (0.70–312 mg/kg dw), epicatechin (1.75–244 mg/kg dw), procyanidin B1 + B2 (4.08–358 mg/kg dw) and quercetin-3-glucoside (0.96–231 mg/kg dw). This research underlies the great potential of traditional apple varieties as a source of natural antioxidants and polyphenolics

Influence of polyphenols on the resistance of traditional and conventional apple varieties to infection by <i>Penicillium expansum</i> during cold storage

This study investigates the impact of polyphenols on the susceptibility of traditional and conventional apple varieties to Penicillium expansum infection and subsequent patulin biosynthesis during cold storage. Traditional varieties, notably ‘Bobovec’, exhibit significantly higher levels of total polyphenols (650.56 ± 9.85 mg/L) and flavonoids (184.11 ± 1.48 g/kg dw) compared to conventional ones after six months of storage, accompanied by the identification of key polyphenols such as chlorogenic acid, epicatechin, phloridzin, quercetin and procyanidins B1 and B2. These traditional varieties demonstrate enhanced resistance to P. expansum infection, as evidenced by prolonged periods for colony formation, particularly ‘Bobovec’ with an average of 384 h. Furthermore, the traditional variety ‘Winter Banane’ and conventional varieties ‘Idared’ and ‘Fuji’ showed increased patulin biosynthesis postinoculation, indicating higher susceptibility to fungal infection. The findings underscore the potential of polyphenols from traditional apple varieties as natural defences against fungal infections, suggesting the importance of selecting or breeding varieties with higher polyphenol content to improve resistance to postharvest pathogens, thereby enhancing the quality and safety of stored apples.<br/