论文部分内容阅读
Abstract: Pistachio nut cream is a new product that was produced by mixing powdered sugar, roasted pistachio nut, defatted powdered milk, lecithin, vanilla and margarine. Pistachio nut cream was stored at 4 and 20 °C in sealed jars. Nut creams were analyzed by chemical analysis such as peroxide values (meq kg-1), total and free fatty acidity (%), moisture content (%), pH, 2-tiobarbutric acid and browning indices. Sensory evaluations of the cream were examined according to the color, odour, texture, taste, aroma and feelings by the panelists. Samples containing 10% and 15% pistachio nut that were stored at 4 °C were better and more acceptable with respect to the chemical properties of pistachio nut cream compared to the nut cream samples that were stored at 20 °C.
Key words: Cream production, pistachio nut, nut proportion, quality.
1. Introduction
Pistachio nut is mainly grown in many regions of the world, such as Iran, USA, Turkey, Greece, and Italy. It is consumed as salted, roasted and also used in dessert production such baklava and nut cream production in Turkey especially Gaziantep and ?anliurfa region as a main ingredient. Pistachio nut contains K, P and also various amounts of Ca, Mg, and Fe. Pistachio nut production is 35,000 tons annually in Turkey. The different cultivars of pistachios are grown in southeast region in our country such as Siirt, Ohadi, Halebi, Kirmizi, and Uzun. Pistachio nut contains 22% of protein, 55% of fat, 18% of carbohydrate and 5% of moisture [1]. Fatty acid content of pistachio nut is 7%-10.5% of palmitic, 0.9%-2.5% of stearic, 54%-71% of oleic, 16%-35% of linoleic acid [2]. Pistachio nut is being used in the production of baklava (special type of dessert in Turkey) and nut paste. Dried pistachios are highly susceptible to lipid oxidation because of high content of lipids and lipid oxidation causes off-flavor development that concern for the shelf life stability of many confections containing pistachios [3]. Nuts are rich in chemical composition and nutrients. Beneficial effects of nuts are attributed to some characteristics of polyunsaturated/saturated fat ratio and high percentage of monounsaturated fat and high-fiber content [4]. The dessert producers prefer Kirmizi and Uzun cultivars in baklava and nut paste production, due to their special green color, flavour and texture. Pistachio nut paste is a sweet product having a semi-hard texture which is produced by mixing the ground pistachio with glucose-sucrose solution. The mixture is kneaded up to desire texture obtained [5]. Different products can be produced by using nut having different texture such as peanut paste [6], walnut paste [7], pistachio nut paste[5], hazelnut paste [8], chocolate peanut spread [9], During the production of nut containing foods, they are subjected to heat treatment and most common application is roasting of nuts. During the heat treatment especially roasting, desirable flavor and aroma development occur. Chemical and biological changes of
nut lipids are detected due to heat treatment such as free fatty acidity, iodine, peroxide and acid values of oils [4]. Proteins of acid-soluble fraction are sensitive to the heat treatment and may have a role in flavor volatile production during the roasting process [10].
Spreadable nut cream is a new product produced by mixing powdered sugar, roasted pistachio nut, defatted milk powder, lecithin, powdered vanilla and margarine until the desire cream shape is obtained [11, 12]. The nut cream contains water, higher amount sugar and fat. Due to the components deteriorative reactions may occur during the long-term of storage of the product. The pistachio nut paste changed its color to brown at high water activities and the occurence of brown color may be due to Maillard reactions [13]. Long-terms storage of foods that contain sugar, water, fat and protein causes deteriorative reactions, browning, lipid oxidation and microbial growth [14]. The moisture effects can be explained in terms of water activity values and it is an important factor for finished food stability.
There was a similar study that was based on the pistachio nut in literature which contains glucose-sucrose mixture and pistachio nut [5]. The aim of this research was to produce a new product that contains margarine, sugar, lecithin, milk powder and vanilla by using pistachio nut having the property of spreadability within different amounts of pistachio nut and also determine the factors affecting the quality of this nut cream during the storage.
2. Materials and Methods
2.1 Materials
Pistachio nut cream was produced roasting nut and adding ingredients to the mixture. The pistachio nuts were roasted at 160-165 °C for 8-10 min. Roasted pistachio nuts were grounded and powdered sugar and defatted powdered milk were added. Margarine, lecithin and also powdered vanilla were added to the mixture. The mixing procedure was carried out until the desire spreadable texture obtained. In the
3. Results and Discussions
The pistachio nut cream contained carbohydrate, moisture, ash, protein, cellulose and fat (Table 1). The results showed that the spreadable nut cream contained
higher amount of carbohydrate due to sugar content. The composition of the nut cream varied due to the pistachio nut content. The changes in chemical parameters of spreadable pistachio nut cream were presented in Table 2. As depicted in Tables 3 and 4, pistachio nut proportions, storage temperatures, and storage period affected the chemical parameters of the nut cream significantly (P < 0.01).
The peroxide values of nut samples stored in glass jars increased due to the increasing amount of pistachio nut (5%, 10% and 15%). The spreadable nut cream samples that contained 5 % pistachio nut had the lowest PO values (0.1695 meq kg-1). The higher storage temperature and content of pistachio nut have resulted in higher peroxide values (Table 3). Increase in storage temperature caused an increase in total and free fatty acidity (%) and decrease in pH values of pistachio nut cream.
Increase in peroxide values of the nut cream could be attributed to the oxidation of fats in the samples. Increase in storage temperatures causes the oxidation of fats containing non-saturated fatty acids such as pistachio nut paste [5] and walnut paste [7], producing alkyl peroxides during the storage periods.
The peroxide values of spreadable nut cream increased from 0.0873 to 0.5494 (meq kg-1) during the storage period (Fig. 1). Peroxide values were used as an indicator of the formation of hydroperoxide due to lipid oxidation for foods that contain pistachio nuts [3].
pH values of pistachio nut cream were different and it was reversely proportional to the pistachio nut proportion (Table 3). Increase in pistachio nut amount caused increases in total and free fatty acidity (%) of
0.01 level (Table 6) and no effect on peroxide value, free fatty acidity (%), browning indice and 2-tiobarbutric acid of pistachio nut cream.
The nut cream containing 5% pistachio had lower free fatty acidity compared to samples that contained 10% and 15% pistachio (Table 2). Free fatty acidity of the spreadable nut cream varied between 0.2758% and 0.6553% as an oleic acid content during the storage period (Fig. 5). There was a sharp increase in free acidity until the third period; afterwards there was slight increase in free acidity of the nut samples. Similarly, the free fatty acidity (%) and total acidity (%) of pistachio nut (dessert type) [5] and walnut paste samples [7] increased during the storage period. Increase in storage temperature caused an increase in total and free fatty acidity (%) of the samples.
The browning indices of spreadable nut cream (A420) varied from 0.369 to 0.532 during the storage period. The nut cream that contain 5% pistachio nut had a lower browning indices compared to samples that contain 10% and 15% pistachio nut (Fig. 6). Foods that contain higher amount of sugar and protein, browning reactions may occur due to Maillard reactions in pistachio nut cream at higher water activity values and also higher storage temperatures with time [13]. It is reported that there is a relation between an increase in total acidity and temperature meanwhile the changes in color from green to yellow- dirty green (formation of pheophytin) [24].
2-Tiobarbutric acid (TBA) values of the spreadable nut cream (A530) varied from 0.121 to 0.275 during the storage period at 4 and 20 °C (Fig. 7). TBA is used as reagent to indicate rancidity in the food materials that contain polyunsaturated fatty acids. It condenses with malonaldehydes that a product of linoleate producing a pink color and reacting with aldehydes causing orange color [20]. TBA test is commonly used for the edibility of the fatty foods such as walnut and pistachio nut paste. Pistachio nut cream that contain 5% proportion of nut had lower TBA values. Increase in pistachio content caused an increase in TBA values of pistachio nut cream. The relationship was statistically significant (P< 0.01) in pistachio amounts in general. TBA values of the spreadable nut sample were close to each other during the storage period.
Spreadable pistachio nut cream is nutritious and preferred product among the breakfast foods especially children. A new product was produced at different pistachio amounts and some chemical parameters were
examined during the storage period of the nut samples. Spreadable nut samples that contain 10% and 15% pistachio nut gave better results in chemical parameters, so it can be produced at this proportions (10% and 15% pistachio nut). Nut samples at 4 °C were more acceptable compared to that were stored at 20 °C due to low deteriorative reactions. Sensory evaluations of the spreadable nut cream were examined monthly according to the color, odour, texture, taste-aroma and feelings in the mouth by panelists. The averages of the sensory evaluations of the nut cream were varied due to different pistachio amounts in the spreadable nut cream(Table 7).
Especially storage periods and temperatures, the averages in the sensory evaluations decreased from the fourth period. Changes in color were considered as a negative effect by the panelists and for this reason the averages of the spreadable nut cream decreased.
4. Conclusion
According to the results of some chemical parameters, spreadable nut cream that were stored at 4 °C had lower peroxide values (meq kg-1) and total acidity (%) compared to the nut cream that stored at 20 °C. Storage temperature, pistachio proportion and storage period affected chemical parameters of nut cream significantly (P < 0.01). Samples containing 10% and 15% pistachio nut were more acceptable due to sensory evaluations. The creams that contain 10% and 15% of pistachio nut are advisable as a new product and it is tought for supplying to the economical incomes to the producers.
References
[1] M. Pala, M. Y?ld?z, F. A?kurt, M. L?ker, The composition of pistachio nut that grown in Turkey, Journal of Food Technology 6 (19) (1994) 405-409.
[2] E. Kü?ük?ner, B. Yurt, Chemical composition and fatty acid contents of pistachio nuts produced in Turkey, GAP II Sgricultural Congress Book, ?anliurfa (2001) 345-352.
[3] M. Javanmard, Shelf life of whey protein-coated pistachio kernel, Journal of Food Process Engineering 31 (2008) 247-259.
[4] N. ?a?la?rmak, A.C. Batkan, Nutrients and biochemistry of nuts in different consumption types in Turkey, J. Food Proc. Preserv 29 (2005) 407-423.
[5] O.F. Gaml?, I. Hayo?lu, The effect of the different packaging and storage conditions on the quality of pistachio nut paste, Journal of Food Engineering 78 (2007) 443-448.
[6] L.R. Beuchat, Relationship of water activity to moisture content ?n tree nuts, Journal of Food Quality 29 (6) (2006) 643-657.
[7] B. Torun, The Production Methods of Walnut Cream, Improving the Shelf Life and Quality, Institute of Natural and Applied Science, Mediterrian Univ. Antalya, 1999.
[8] S.N. Ercan, M. Derviso?lu, Study of the steady flow behavior of hazelnut paste, Journal of Food Process Engineering 21 (1) (1998) 81-190.
[9] C.A. Chu, A.V.A. Resureccion, Sensory profiling and characterization of chocolate peanut spread using response surface methodology, Journal of Sensory Studies 20 (2005) 243-274.
[10] A.P. Adebiyi, I.A. Adeyemi, A.O. Olurundu, Effects of processing conditions and packaging material on quality attributes of dry-roasted peanuts, Journal of Food Science Agric. 13 (2000) 1465-1471.
[11] A. Altan, Special Products Production, Agricultural Faculty, ?ukurova University, Adana, Turkey, 1992.
[12] O. Y?lmaz, Production of Chocolate, The General Research and Progressive Headmaster, The Industry and Trade Ministry, Ankara, Turkey, 1997.
[13] M. Maskan, F. G??ü?, The fittings of various models to water sorption isotherms of pistachio nut paste, Journal of Food Engineering 33 (1997) 227-237.
[14] J.M. Jay, Modern Food Microbiology, 3rd ed., Van Nostrand Reinhold, New York, 1986, pp. 40-41.
[15] AOAC, Official Methods of Analysis, Association of Official Analytical Chemists International, Arlington, VA, 1999.
[16] S. Nas, H.Y. G?kalp, M. ünsal, Vegetable Oil Technology, The Pub. of Faculty of Agric?ulture, Atatürk Univ. Erzurum, No.723, 1992.
[17] H. ?zkaya, B. Kahveci, The Methods of Analysis of Cereal Products, Food Technology Pub. Ankara, 1990.
[18] AOAC, Official Methods of Analysis, Association of Official Agricultural Chemists, 11th ed., 1990, pp. 1015-1017.
[19] M. Shaul, S. Israel, J.K. Isaisa, Browning determination in citrus product, Journal of Agricultural and Food Chemistry 25 (3) (1977) 179-186.
[20] C.J. Rudolph, G.V. Odell, Chemical changes in pecan oils during oxidation, Journal of Food Quality 15 (1992) 279-293.
[21] W.A. Gould, Food Quality Assurance, The Avi. Publishing Company, Wesport, Connect?cut (1976) 356-361.
[22] T. Altu?, G. Ova, K. Demira?, U. Kurtcan, Food Quality Control, 157, Aegean Univ. Engineering Pub. No. 29?zmir, 1995.
[23] A. Elgün, M. Certel, Z. Ertugay, H.G. Kotanc?lar, The Analytical Quality Controls and Laboratory Application Manuals for Agricultural Products, Faculty of Agriculture, Atatürk Univ., Erzurum, 1998, pp. 56-58
[24] B. Cemero?lu, J. Acar, Fruit and Vegetable Processing Thecnology, Ankara, 1986.
Key words: Cream production, pistachio nut, nut proportion, quality.
1. Introduction
Pistachio nut is mainly grown in many regions of the world, such as Iran, USA, Turkey, Greece, and Italy. It is consumed as salted, roasted and also used in dessert production such baklava and nut cream production in Turkey especially Gaziantep and ?anliurfa region as a main ingredient. Pistachio nut contains K, P and also various amounts of Ca, Mg, and Fe. Pistachio nut production is 35,000 tons annually in Turkey. The different cultivars of pistachios are grown in southeast region in our country such as Siirt, Ohadi, Halebi, Kirmizi, and Uzun. Pistachio nut contains 22% of protein, 55% of fat, 18% of carbohydrate and 5% of moisture [1]. Fatty acid content of pistachio nut is 7%-10.5% of palmitic, 0.9%-2.5% of stearic, 54%-71% of oleic, 16%-35% of linoleic acid [2]. Pistachio nut is being used in the production of baklava (special type of dessert in Turkey) and nut paste. Dried pistachios are highly susceptible to lipid oxidation because of high content of lipids and lipid oxidation causes off-flavor development that concern for the shelf life stability of many confections containing pistachios [3]. Nuts are rich in chemical composition and nutrients. Beneficial effects of nuts are attributed to some characteristics of polyunsaturated/saturated fat ratio and high percentage of monounsaturated fat and high-fiber content [4]. The dessert producers prefer Kirmizi and Uzun cultivars in baklava and nut paste production, due to their special green color, flavour and texture. Pistachio nut paste is a sweet product having a semi-hard texture which is produced by mixing the ground pistachio with glucose-sucrose solution. The mixture is kneaded up to desire texture obtained [5]. Different products can be produced by using nut having different texture such as peanut paste [6], walnut paste [7], pistachio nut paste[5], hazelnut paste [8], chocolate peanut spread [9], During the production of nut containing foods, they are subjected to heat treatment and most common application is roasting of nuts. During the heat treatment especially roasting, desirable flavor and aroma development occur. Chemical and biological changes of
nut lipids are detected due to heat treatment such as free fatty acidity, iodine, peroxide and acid values of oils [4]. Proteins of acid-soluble fraction are sensitive to the heat treatment and may have a role in flavor volatile production during the roasting process [10].
Spreadable nut cream is a new product produced by mixing powdered sugar, roasted pistachio nut, defatted milk powder, lecithin, powdered vanilla and margarine until the desire cream shape is obtained [11, 12]. The nut cream contains water, higher amount sugar and fat. Due to the components deteriorative reactions may occur during the long-term of storage of the product. The pistachio nut paste changed its color to brown at high water activities and the occurence of brown color may be due to Maillard reactions [13]. Long-terms storage of foods that contain sugar, water, fat and protein causes deteriorative reactions, browning, lipid oxidation and microbial growth [14]. The moisture effects can be explained in terms of water activity values and it is an important factor for finished food stability.
There was a similar study that was based on the pistachio nut in literature which contains glucose-sucrose mixture and pistachio nut [5]. The aim of this research was to produce a new product that contains margarine, sugar, lecithin, milk powder and vanilla by using pistachio nut having the property of spreadability within different amounts of pistachio nut and also determine the factors affecting the quality of this nut cream during the storage.
2. Materials and Methods
2.1 Materials
Pistachio nut cream was produced roasting nut and adding ingredients to the mixture. The pistachio nuts were roasted at 160-165 °C for 8-10 min. Roasted pistachio nuts were grounded and powdered sugar and defatted powdered milk were added. Margarine, lecithin and also powdered vanilla were added to the mixture. The mixing procedure was carried out until the desire spreadable texture obtained. In the
3. Results and Discussions
The pistachio nut cream contained carbohydrate, moisture, ash, protein, cellulose and fat (Table 1). The results showed that the spreadable nut cream contained
higher amount of carbohydrate due to sugar content. The composition of the nut cream varied due to the pistachio nut content. The changes in chemical parameters of spreadable pistachio nut cream were presented in Table 2. As depicted in Tables 3 and 4, pistachio nut proportions, storage temperatures, and storage period affected the chemical parameters of the nut cream significantly (P < 0.01).
The peroxide values of nut samples stored in glass jars increased due to the increasing amount of pistachio nut (5%, 10% and 15%). The spreadable nut cream samples that contained 5 % pistachio nut had the lowest PO values (0.1695 meq kg-1). The higher storage temperature and content of pistachio nut have resulted in higher peroxide values (Table 3). Increase in storage temperature caused an increase in total and free fatty acidity (%) and decrease in pH values of pistachio nut cream.
Increase in peroxide values of the nut cream could be attributed to the oxidation of fats in the samples. Increase in storage temperatures causes the oxidation of fats containing non-saturated fatty acids such as pistachio nut paste [5] and walnut paste [7], producing alkyl peroxides during the storage periods.
The peroxide values of spreadable nut cream increased from 0.0873 to 0.5494 (meq kg-1) during the storage period (Fig. 1). Peroxide values were used as an indicator of the formation of hydroperoxide due to lipid oxidation for foods that contain pistachio nuts [3].
pH values of pistachio nut cream were different and it was reversely proportional to the pistachio nut proportion (Table 3). Increase in pistachio nut amount caused increases in total and free fatty acidity (%) of
0.01 level (Table 6) and no effect on peroxide value, free fatty acidity (%), browning indice and 2-tiobarbutric acid of pistachio nut cream.
The nut cream containing 5% pistachio had lower free fatty acidity compared to samples that contained 10% and 15% pistachio (Table 2). Free fatty acidity of the spreadable nut cream varied between 0.2758% and 0.6553% as an oleic acid content during the storage period (Fig. 5). There was a sharp increase in free acidity until the third period; afterwards there was slight increase in free acidity of the nut samples. Similarly, the free fatty acidity (%) and total acidity (%) of pistachio nut (dessert type) [5] and walnut paste samples [7] increased during the storage period. Increase in storage temperature caused an increase in total and free fatty acidity (%) of the samples.
The browning indices of spreadable nut cream (A420) varied from 0.369 to 0.532 during the storage period. The nut cream that contain 5% pistachio nut had a lower browning indices compared to samples that contain 10% and 15% pistachio nut (Fig. 6). Foods that contain higher amount of sugar and protein, browning reactions may occur due to Maillard reactions in pistachio nut cream at higher water activity values and also higher storage temperatures with time [13]. It is reported that there is a relation between an increase in total acidity and temperature meanwhile the changes in color from green to yellow- dirty green (formation of pheophytin) [24].
2-Tiobarbutric acid (TBA) values of the spreadable nut cream (A530) varied from 0.121 to 0.275 during the storage period at 4 and 20 °C (Fig. 7). TBA is used as reagent to indicate rancidity in the food materials that contain polyunsaturated fatty acids. It condenses with malonaldehydes that a product of linoleate producing a pink color and reacting with aldehydes causing orange color [20]. TBA test is commonly used for the edibility of the fatty foods such as walnut and pistachio nut paste. Pistachio nut cream that contain 5% proportion of nut had lower TBA values. Increase in pistachio content caused an increase in TBA values of pistachio nut cream. The relationship was statistically significant (P< 0.01) in pistachio amounts in general. TBA values of the spreadable nut sample were close to each other during the storage period.
Spreadable pistachio nut cream is nutritious and preferred product among the breakfast foods especially children. A new product was produced at different pistachio amounts and some chemical parameters were
examined during the storage period of the nut samples. Spreadable nut samples that contain 10% and 15% pistachio nut gave better results in chemical parameters, so it can be produced at this proportions (10% and 15% pistachio nut). Nut samples at 4 °C were more acceptable compared to that were stored at 20 °C due to low deteriorative reactions. Sensory evaluations of the spreadable nut cream were examined monthly according to the color, odour, texture, taste-aroma and feelings in the mouth by panelists. The averages of the sensory evaluations of the nut cream were varied due to different pistachio amounts in the spreadable nut cream(Table 7).
Especially storage periods and temperatures, the averages in the sensory evaluations decreased from the fourth period. Changes in color were considered as a negative effect by the panelists and for this reason the averages of the spreadable nut cream decreased.
4. Conclusion
According to the results of some chemical parameters, spreadable nut cream that were stored at 4 °C had lower peroxide values (meq kg-1) and total acidity (%) compared to the nut cream that stored at 20 °C. Storage temperature, pistachio proportion and storage period affected chemical parameters of nut cream significantly (P < 0.01). Samples containing 10% and 15% pistachio nut were more acceptable due to sensory evaluations. The creams that contain 10% and 15% of pistachio nut are advisable as a new product and it is tought for supplying to the economical incomes to the producers.
References
[1] M. Pala, M. Y?ld?z, F. A?kurt, M. L?ker, The composition of pistachio nut that grown in Turkey, Journal of Food Technology 6 (19) (1994) 405-409.
[2] E. Kü?ük?ner, B. Yurt, Chemical composition and fatty acid contents of pistachio nuts produced in Turkey, GAP II Sgricultural Congress Book, ?anliurfa (2001) 345-352.
[3] M. Javanmard, Shelf life of whey protein-coated pistachio kernel, Journal of Food Process Engineering 31 (2008) 247-259.
[4] N. ?a?la?rmak, A.C. Batkan, Nutrients and biochemistry of nuts in different consumption types in Turkey, J. Food Proc. Preserv 29 (2005) 407-423.
[5] O.F. Gaml?, I. Hayo?lu, The effect of the different packaging and storage conditions on the quality of pistachio nut paste, Journal of Food Engineering 78 (2007) 443-448.
[6] L.R. Beuchat, Relationship of water activity to moisture content ?n tree nuts, Journal of Food Quality 29 (6) (2006) 643-657.
[7] B. Torun, The Production Methods of Walnut Cream, Improving the Shelf Life and Quality, Institute of Natural and Applied Science, Mediterrian Univ. Antalya, 1999.
[8] S.N. Ercan, M. Derviso?lu, Study of the steady flow behavior of hazelnut paste, Journal of Food Process Engineering 21 (1) (1998) 81-190.
[9] C.A. Chu, A.V.A. Resureccion, Sensory profiling and characterization of chocolate peanut spread using response surface methodology, Journal of Sensory Studies 20 (2005) 243-274.
[10] A.P. Adebiyi, I.A. Adeyemi, A.O. Olurundu, Effects of processing conditions and packaging material on quality attributes of dry-roasted peanuts, Journal of Food Science Agric. 13 (2000) 1465-1471.
[11] A. Altan, Special Products Production, Agricultural Faculty, ?ukurova University, Adana, Turkey, 1992.
[12] O. Y?lmaz, Production of Chocolate, The General Research and Progressive Headmaster, The Industry and Trade Ministry, Ankara, Turkey, 1997.
[13] M. Maskan, F. G??ü?, The fittings of various models to water sorption isotherms of pistachio nut paste, Journal of Food Engineering 33 (1997) 227-237.
[14] J.M. Jay, Modern Food Microbiology, 3rd ed., Van Nostrand Reinhold, New York, 1986, pp. 40-41.
[15] AOAC, Official Methods of Analysis, Association of Official Analytical Chemists International, Arlington, VA, 1999.
[16] S. Nas, H.Y. G?kalp, M. ünsal, Vegetable Oil Technology, The Pub. of Faculty of Agric?ulture, Atatürk Univ. Erzurum, No.723, 1992.
[17] H. ?zkaya, B. Kahveci, The Methods of Analysis of Cereal Products, Food Technology Pub. Ankara, 1990.
[18] AOAC, Official Methods of Analysis, Association of Official Agricultural Chemists, 11th ed., 1990, pp. 1015-1017.
[19] M. Shaul, S. Israel, J.K. Isaisa, Browning determination in citrus product, Journal of Agricultural and Food Chemistry 25 (3) (1977) 179-186.
[20] C.J. Rudolph, G.V. Odell, Chemical changes in pecan oils during oxidation, Journal of Food Quality 15 (1992) 279-293.
[21] W.A. Gould, Food Quality Assurance, The Avi. Publishing Company, Wesport, Connect?cut (1976) 356-361.
[22] T. Altu?, G. Ova, K. Demira?, U. Kurtcan, Food Quality Control, 157, Aegean Univ. Engineering Pub. No. 29?zmir, 1995.
[23] A. Elgün, M. Certel, Z. Ertugay, H.G. Kotanc?lar, The Analytical Quality Controls and Laboratory Application Manuals for Agricultural Products, Faculty of Agriculture, Atatürk Univ., Erzurum, 1998, pp. 56-58
[24] B. Cemero?lu, J. Acar, Fruit and Vegetable Processing Thecnology, Ankara, 1986.