Dondurulmuş sebze uretiminde ohmik ısıtma on işleminin kalite uzerine etkisi
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Date
2019-09-02
Authors
Dağdelen, Canan
Journal Title
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Publisher
Bursa Uludağ Üniversitesi
Abstract
Günümüzde ticari olarak kullanılan gıda işleme yöntemlerine alternatif yeni yöntemler araştırılmaktadır. Besin değeri ve kalitesi yüksek gıdalar üretmek için kullanılan bu yöntemlerden biri de adını ohm kanunundan alan ohmik ısıtma tekniğidir. Bu çalışmada sebzelerin doğal tadının, yapısının, görünüşünün, renginin, lezzetinin ve bileşiminin en iyi şekilde korunmasını sağlayan yöntemlerden biri olan dondurarak muhafaza prosesinde, ürün kalitesini yükseltmek amacıyla, klasik haşlama işlemine alternatif olarak ohmik ısıtma ön işlemi kullanımı amaçlanmıştır. Bu amaçla dondurarak üretimi yaygın olan yeşil fasülyelerin (Phaseolus vulgaris L.) sapları ayrılmış, 40-60 mm boyunda kesildikten sonra bir kısmı ohmik ıstma yöntemiyle, bir kısmı geleneksel yöntem ile peroksidaz enzimi inaktivasyonu baz alınarak haşlanmış ve IQF yöntemiyle dondurulmuştur. Ev tipi üretimi temsilen geleneksel haşlama yapılan fasülyenin bir kısmı da derin dondurucuda yavaş dondurmaya bırakılmıştır. Ohmik ısıtma yöntemi ve geleneksel yöntem ile haşlanarak dondurulan ve 12 ay boyunca depolanan fasülyeler antioksidan kapasite, toplam fenolik madde, klorofil a, klorofil b, toplam klorofil miktarları ve renk ile birlikte toplam canlı mikroorganizma, toplam koliform, maya-küf, Escherichia coli, Listeria monocytogenes ve Escherichia coli O157:H7 yönünden analiz edilmiştir. Sonuçta, ohmik ısıtma yöntemiyle haşlanıp dondurulan üründe antioksidan kapasite (7,41 mmol T.E./100 g KM), geleneksel yöntem ve ev tipine göre daha fazla azalmış, toplam fenolik madde miktarı (0,29 mg/g KM) geleneksel yönteme göre düşmüş, ancak ev tipine göre artmıştır. Klorofil miktarı (8,85 mg/100g KM) ve renk değerlerinin ise geleneksel yönteme ve ev tipine göre daha iyi korunduğu ortaya konmuştur. İstatistiksel olarak ise farklı haşlama yöntemleri, klorofil miktarları hariç, incelenen diğer tüm parametreler arasında önemli farklılığa neden olmuştur. Depolama süresince saptanan kimyasal analiz sonuçları arasındaki farklılıklar önemli bulunurken, ön işlem ve depolama süresi interaksiyonunun sadece renk değerleri açısından (L ve c hariç) farklılık göstermediği saptanmıştır (p<0,05). Mikrobiyolojik analiz sonuçlarına göre ise taze fasülyede bulunan mikroorganizma sayısı tüm işlem koşullarında azalmış ve ürünler özellikle patojenler yönünden güvenilir bulunmuştur.
Nowadays, alternative methods to commercially used food processing methods are being investigated. One of these methods used to produce foods with high nutritional value and quality is the ohmic heating technique which takes its name from the ohm's law. In this study, ohmic heating pre-treatment was used as an alternative to the conventional blanching process in order to improve the product quality in the frozen food process. Freezing is one of the methods that provide the best preservation for the taste, structure, appearance, color, flavor and composition of the vegetables. For this purpose, frozen green beans (Phaseolus vulgaris L.), which are widely preserved by freeze production, were used. Firstly the stems were removed and the vegetable was cut to a length of 40-60 mm. One part was blanched in the ohmic heating apparatus and the other part was blanched by the conventional method until the peroxidase enzyme was inactive. Then both vegetables were frozen by using IQF. Some of the conventional blanced beans representing home production were also allowed to freeze slowly in the freezer. The products were stored for 12 months in the frozen warehouse. During the storage, they were evaluted for total phenolic content, antioxidant capacity, chlorophyll a, chlorophyll b, total chlorophyll amount and color. Also contents and presence of total live microorganisms, yeast-mold, total coliform, Escherichia coli, Listeria monocytogenes and Escherichia coli O157: H7 were analyzed. As a result, the antioxidant capacity of the ohmic heating method (7,41 mmol TE/100 g DM), was decreased more than the traditional method and house type. While the total amount of phenolic matter (0,29 mg/g DM) was increased compared to the home type traditional method, it was reduced compared to conventional method. The amount of chlorophyll (8,85 mg/100g DM) and color values were better preserved in frozen beans blanched with ohmic heating. Statistically, different blanching methods caused significant difference between all the parameters examined except chlorophyll amounts. While the differences between the chemical analysis results were significant during storage, blanching method and storage time interaction did not differ only in terms of color values (except L and c values) (p <0,05). According to the results of microbiological analysis, the number of microorganisms in fresh beans decreased in all processing conditions and the products were found to be reliable especially in terms of pathogens.
Nowadays, alternative methods to commercially used food processing methods are being investigated. One of these methods used to produce foods with high nutritional value and quality is the ohmic heating technique which takes its name from the ohm's law. In this study, ohmic heating pre-treatment was used as an alternative to the conventional blanching process in order to improve the product quality in the frozen food process. Freezing is one of the methods that provide the best preservation for the taste, structure, appearance, color, flavor and composition of the vegetables. For this purpose, frozen green beans (Phaseolus vulgaris L.), which are widely preserved by freeze production, were used. Firstly the stems were removed and the vegetable was cut to a length of 40-60 mm. One part was blanched in the ohmic heating apparatus and the other part was blanched by the conventional method until the peroxidase enzyme was inactive. Then both vegetables were frozen by using IQF. Some of the conventional blanced beans representing home production were also allowed to freeze slowly in the freezer. The products were stored for 12 months in the frozen warehouse. During the storage, they were evaluted for total phenolic content, antioxidant capacity, chlorophyll a, chlorophyll b, total chlorophyll amount and color. Also contents and presence of total live microorganisms, yeast-mold, total coliform, Escherichia coli, Listeria monocytogenes and Escherichia coli O157: H7 were analyzed. As a result, the antioxidant capacity of the ohmic heating method (7,41 mmol TE/100 g DM), was decreased more than the traditional method and house type. While the total amount of phenolic matter (0,29 mg/g DM) was increased compared to the home type traditional method, it was reduced compared to conventional method. The amount of chlorophyll (8,85 mg/100g DM) and color values were better preserved in frozen beans blanched with ohmic heating. Statistically, different blanching methods caused significant difference between all the parameters examined except chlorophyll amounts. While the differences between the chemical analysis results were significant during storage, blanching method and storage time interaction did not differ only in terms of color values (except L and c values) (p <0,05). According to the results of microbiological analysis, the number of microorganisms in fresh beans decreased in all processing conditions and the products were found to be reliable especially in terms of pathogens.
Description
Keywords
Fasülye, Green bean, IQF, Ohmik ısıtma, Antioksidan kapasite, Ohmic heating, Antioxidant capacity
Citation
Dağdelen, C. (2019). Dondurulmuş sebze üretiminde ohmik ısıtma on işleminin kalite uzerine etkisi. Yayınlanmamış yüksek lisans tezi. Bursa Uludağ Üniversitesi Fen Bilimleri Enstitüsü.