Hıyar turşularında sorbik asitin yüzeyde zar oluşumuna etkisi üzerinde bir araştırma

Abstract

63 SUMMARY Considerable losses may occur due to the film which forms on the surface of the brine of pickled cucumbers and therefore has a negative effect on the quality of the pickles. In this research, ef fect of sorbic acid on the film which forms on the surface of the brine of the pickled cucumbers which were prepared at the experimen tal conditions was tried for to determine. The concentrations of the salt brine were 5 % and 10 %. Next while potassium sorbate was added at desired concentration (0.05 %, 0.1 `h and 0.2 %) some jars were left without potassium sor bate. In experiment 1 kg. glass jars were used and every each treat ment has five jars. In 3 of 5 jars, chemical and microbiological analyses were made, other 2 jars were used for observations. After the cucumber prepared, the acidity and pii of brines in each jar were determined during the 45 days. During the fermentation, yeast and mold populations were determined at the and of the 1 st, 2 nd, 3 rd and 4 th week. And effect of potassium sorbate on growth of yeast and fermentation of brined cucumbers was investigated. At the begining every each two days salt concentration was determined and added in appropriate amounts in brine to maintain the desired initial concentration. The formation of film odour, blur of brine, formation of deposit and changes of cotour on cucumber were also observed. Later effect of isolated yeasts, obtained from brines to formation on film was determined and by this way corre lation between formation of film and yeasts populations was investigated. J?he results of the research are outlined below; 1- At the end of 7 th day, maximum brine acidity as lactic {%) was determined at the control brines with 5 %.salt and without potassium sorbate. In the higher salt concentration (10 %) acid fermentation being somewhat delayed. At the end of 11 th day acidity reached to maximum degree. 2- At the all brines with 5 I7` salt concentration, mean acid value were found 0.84 # (as lactic acid). But belongs to brines 10 l/o salt was * 0.38 %.64 3- It was found that the formation of film at surface caused to ' decrease acidity of brine, tfhile acidity raised gradually at 5 L/o salt concentrated brine in first week, at controls the formation of film caused lowest acidity which was high before the formation of film. At the brines which contain 5 % salt and potassium sorbate, there was no no formation of film but raising acidity during the one month was observed and later it stayed same value. 4- Acidity at brines with 5 ç/° salt and without potassium sorbate was lower then of the brine with 5 li'° salt and potassium sorbate. There is no. significant difference between values of titratable acidity obtained from brines (10 fo salt) with and without potassium sorbate. 5- pH in all jars decreased rapidly during first 4 days. After first 4 day, pH begun to raise in 5 cf° salt concentrated brine. p# of the brine which contains potassium sorbate went on to decrease. The level of pH of 10 io salt concentrated brines stayed steaty. 6- The amount of salt, in all brines, decreased at early days and fixed equilibrium was obtained at 7 th - 10 th days. 7- It was found that there was no effect of application of various rate of potassium sorbate on changing levels of salt in brine. 8- There was no yeast and mold growth in the brines which contain 0.1 % and. 0.2 % potassium sorbate. But growth of yeast and. mold could not inhibited in the same brines (especially 10 ','a salt) with 0.5 % patassium sorbate. 9- The «east counts which is determined in 10 % salt concentrated brines was higher than that of 5 % salt concentrated brines. The yeast populations 5 % and 10 % salt concentrated of the control jars raised maximum level at the end of 2 nd week but at the end of 4 th week this amount decreased to the level of initial value. 10- It was found that the 78% of the isolated yeasts (60 isolates) was capable of formation of film. 11- 'The formation of film, on the surface of brines which contain 5 % salt and three concentration of potassium sorbate namely 0.05 % » 0.1 /'`, 0.2 İo and on the surface of brine which contain 10 fo salt and- 65 - two concentration of potassium sorbate namely 0.1 %, 0.2 # was inhibited during the 1.5 months. It was also found that yeast counts and film observation showed appropriateness to each other. 12- There was a bad smell in 5 % salt concentrated brine after 4 th day of experiment and later cucumbers, in this brine, softened and be come breakdown. There was also odour which is named film odour in 10 fo salt concentrated control brines. 13- There was fair odour in the brines which contain potassium sorbate during the first two weeks, but acidity odour, observed especially in high salt and potassium sorbate concentrated brine at late daysv of experiment. It was obser that in some jars the colour of cucumbers brined with po tassium sorbate is faded and bleached at late days of fermentation0 14- The observations on quality of pickled cucumbers gave best results obtained from the jars which contain 5 % salt and two concentration namely 0.2 fo, 0.9 İo potassium sorbate. Desired results on acid production and maintaince of its level was obtained from these jars. T« C'