The effect of boiling on qualitative properties of grape juice produced by the traditional method

Abstract

In this study, grape molasses produced by using the traditional methods from the from Taşkent town of Konya were analysed for their some quality values. Depending on the type of grape molasses and boiling periods, some differences were found in physico-chemical properties. Protein, pH, total acid, hydroximetil furfural, soluble dry matter, total phenol and viscosity values were found between 0.260 % and 0.421 %, 7.82 and 8. .47. The K, Mg, Na, P, Ca contents of all the molasses samples has been detected at high levels. At some quality parameters such as protein, total acid and L* values have been decreased towards to end of the boiling period. As a result, antioxidant activity and anthocyanin in the red grape molasses were superior to compared with other types of grape molasses.

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.…”

“…Karadeniz (1999) investigated the mineral composition of some pear juices obtained from different pear varieties and Na, K, Ca, and Mg amounts were determined as 131, 15,700, 271, and 947 mg/kg dry weight, respectively. Mean K, Mg, and Na mineral content of pear pekmez samples were higher than that of carob (Tetik et al, 2010) and grape (Özcan et al, 2015) pekmez but similar with apple pekmez except Na (Kuşçu & Bulantekin, 2016). Higher Ca content might be due to the addition of CaCO 3 during production.…”

“…Compared to the initial pear juice parameters, the lowest L , a , and b changes were observed in the samples treated with zeolite, while the highest decrease was observed in the PP samples. The mean L values of pear pekmez samples produced by three different methods were found to be lower, while a * and b * values were found to be higher than traditional homemade pear (Koca et al, 2007), carob (İnan, Arslan, Taşdemir, & Özcan, 2011; Tetik et al, 2010), grape (İnan et al, 2011; Özcan etal., 2015), mulberry, apricot, and date pekmez (İnan et al, 2011) samples. This difference may be mainly due to the production method.…”

Comparatively Investigation of Grape Molasses Produced by Conventional and Industrial Techniques

“…is considered as an important component in human nutrition and as a good source for energy intake due to its high contents of sugars (glucose, galactose), minerals and organic acids [4]. In Turkey, traditional methods are common way to obtain homemade grape molasses in villages.…”

Sweet pomegranate pekmez production: Effect of different production methods and activated carbon treatment on some quality parameters and 5‐hydroxymethyl furfural formation

“…Özcan et al. (2015) reported a similar reduction in TA% during processing from fruit juice to pekmez during grape pekmez production. The significant decrease in the mean TA% content of AC pekmez samples may be due to the loss of some phenolic acids of pomegranate juices during the application of activated carbon before boiling.…”