The effects of production methods and storage on the chemical constituents of apple pekmez

Abstract

The purposes of this study were to investigate the effects of two different pekmez production methods namely open pan evaporation (OPE) and vacuum evaporation (VE) on the final products, and to observe the changes in constituents as well as aromatic components after 4 months of storage. The initial and poststorage (4 months) 5-hydroxymethyl furfural (HMF) content in OPE apple pekmez were respectively 5.48, and 7.04 mg/kg. No HMF was detected in VE apple pekmez. Both initial and poststorage content of phenolic compounds was higher in VE pekmez compared to OPE pekmez. The effects of production methods and storage time were statistically significant on phenolic compounds in apple pekmez. The content of all analyzed minerals except calcium has significantly decreased in pekmez compared to raw material on dry weight basis. OPE resulted in a 55.97 % loss in the amount of ascorbic acid, whereas the loss in VE has been 23.45 %. Poststorage loss in ascorbic acid has respectively been 69.54, and 89.28 %, for VE and OPE samples. None of the aromatic components of fresh apple was detected in pekmez.

Improved qualitative properties of pear pekmez by natural zeolite treatment during production process

“…On the other hand, HMF contents in pekmez produced by our production method were found to be lower than other studies conducted with grape pekmez (Tosun & Ustun, 2003; 10 mg/kg), mulberry pekmez (Oral, Dogan, Sarioglu, & Toker, 2012;88.2 mg/kg) grape, mulberry, black mulberry, and carob pekmez (Toker et al, 2013;43.66 mg/kg). Our results are consistent with the results obtained by Kuşçu and Bulantekin (2016) for apple pekmez and Özcan, Alpar, and Juhaimi (2015) for white grape, red grape, and black grape molasses. The pekmez processing methods that may have been associated with lower HMF results in this study differed from the traditional processing method in two ways.…”

“…On the other hand, excessive amounts may lead to dark color and undesired taste (Kuşçu & Bulantekin, 2016). SS value of pear pekmez samples produced by three different methods were within the limits (68.4-69 Brix) allowed by TSE (TSE, 2007).…”

“…Clarified pear juice (CPJ) was obtained according to Kuşçu and Bulantekin (2016) and neutralized with CaCO 3 . Three different pekmez samples were produced from clarified and neutralized pear juice with 5 g/L (Method I‐abbreviated as 5ZP) and 10 g/L (Method II‐abbreviated as 10 ZP) zeolite or without zeolite (Method III‐abbreviated as PP) application.…”

“…In general pekmez has been produced from various fruits having high sugar content such as grape, carob, mulberry, apricot, plum, fig, apple, elecampane, watermelon, and sugar beet (Akbulut & Bilgiçli, 2010; Alpaslan & Hayta, 2002; Batu, 2005; Kamiloglu & Capanoglu, 2014; Karababa & Işikli, 2005; Karaca, Saydam, & Güven, 2012; Kuşçu & Bulantekin, 2016; Liyana‐Pathirana, Shahidi, & Alasalvar, 2006; Tosun & Ustun, 2003; In recent years, interest and demand for various food products produced with high antioxidant capacity fruits have increased and the studies in this context have gained popularity. Kamiloglu and Capanoglu (2014) determined the total phenolics, flavonoids, proanthocyanidins, anthocyanins, and antioxidant capacity of grape, mulberry, carob, apricot, and plum molasses and showed that the provided polyphenols have been preserved to a certain degree after digestion.…”

“…These reactions are responsible for the formation of attractive colors and flavors in heat treated foods. However, the over‐treatment often damages the components and reduces nutritional value and quality, as in the case of pekmez (Bozkurt, Göğüş, & Eren, 1999; Kuşçu & Bulantekin, 2016; Rufían‐Henares and de la Cueva, 2008).…”