تاثیر عصاره زنجبیل، اسید سیتریک و اولتراسوند بر ویژگی‌های فیزیکوشیمیایی گوشت شتر

گوشت شتر ارزش تغذیه‌ای بالا و طعم مشابه با سایر منابع گوشت قرمز دارد. در این پژوهش به‌منظور بهبود ویژگی‌های بافتی تاثیر افزودن محلول‌های ماریناد (5 سطح)، زمان (2 سطح) و فرایند اولتراسیون (2 سطح) بر روی گوشت شتر بر پایه طرح کاملا تصادفی مورد بررسی قرار گرفت. قطعات گوشت به دو گروه تقسیم شد و یک گروه تحت فرایند اولتراسیون قرار گرفت. پنج گروه محلول ماریناد (عصاره زنجبیل 30%، عصاره زنجبیل 30%+ 0.5%، %1 و 1.5% اسیدسیتریک و آب مقطر (شاهد)) تهیه شد. قطعات گوشت در داخل محلول ها در دمای c˚1±4 داخل کیسه‌های پلی اتیلنی خوابانده شد. پس از طی 24 و 48 ساعت خصوصیات فیزیکوشیمیایی، شاخص‌های رنگ (a*،b* وl*)، بافت و ساختار میکروسکوپی نمونه‌ها مورد ارزیابی قرار گرفت. نمونه‌های ماریناد شده در عصاره زنجبیل 30% و 1.5% اسیدسیتریک، کمترین میزان ph (بعد از ماریناد و بعد از پخت) و بیشترین میزان افت پخت را نسبت به نمونه شاهد داشتند (p<0/05). برای نمونه‌های گوشت ماریناد شده در عصاره زنجبیل 30%، بالاترین میزان شاخصa*، b* و l* نسبت به نمونه شاهد گزارش شد (p<0/05). زمان و اولتراسیون در بهبود ویژگی‌های بافتی تاثیرگذار بودند. تصاویر میکروسکوپ الکترونی ایجاد تغییرات در ساختار داخلی پروتئین‌های گوشت و افزایش فضای خالی بین میوفیبریل‌ها پس از 48 ساعت را نشان داد. استفاده همزمان از عصاره زنجبیل، اسیدسیتریک و اولتراسوند گزینه مناسب‌تری جهت افزایش تردی گوشت نسبت به نمونه شاهد بود.

Effect of Ginger extract, citric Acid and ultrasound on physicochemical properties of Camel meat

Introductıon: In developing countries, camel meat is used to provide nutrients, proteins, vitamins, and minerals but it usually has a tough texture. Marinating meat may improve its flavor and tenderness. It has been shown that plant enzymes such as papain, ginger, and Cucumis increase the meat apos;s tenderness and improve the flavor and aroma of the products.;Ginger extract (GE) could improve the tenderness of camel meat by “Zingibain”. Marination in acidic solutions has been used both traditionally and industrially for the tenderization and flavoring of meat (Abdeldaiem and Hoda., 2013; Tsai et al., 2012). The tenderization effect of marination on meat have been examined by using organic acids such as citric acid (Aktas et al., 2003; Berge et al., 2001; Ke et al., 2009; Kim et al., 2013; Ke, 2006; Ke et al. 2009).;The objective of this study was to evaluate the effect of ultrasound and marination with different concentrations of citric acid and Ginger extract 30% on the physicochemical characteristics of camel meat.; ;Materials and methods: Fresh ginger rhizome (Zingiber officinalis roscoe) purchased from a local market was washed, peeled, sliced and immediately homogenized with an equal quantity of chilled and distilled water (4ºC) for 2 min to extract the crude enzyme. The homogenate was filtered through Buchner funnel and the water to get the GE. Marinade solutions were prepared by the addition of 0.5, 1 and 1.5% citric acid to 30% GE, and distilled water was used as control. To prepare the required 30% GE, the crude fresh GE was diluted with distilled water (He et al., 2015).;The portions from Biceps femoris muscles of aged male camel carcasses (4 years of age) were prepared according to the method described by Abdeldaiem et al (2013). Uniform sized (3×3×3 cm) of aged camel meat chunks were dipped in the curing solutions at the ratio of 3:1(meat: liquid) and immersed in the polyethylene bags and kept at 4±1°C for 24 and 48 h (Abdeldaeim et al., 2014; Garge et al., 2006).;The pH values were measured directly using a probetype electrode (Naveena et al., 2004). Uptake of the marinade (%) was measured according to the method described by Garg et al (2006) and Hosseini et al (2012).;The color measurements; lightness (L*), redness (a*) and yellowness (b*) were performed at the surface of the marinated meat samples (Barbut, 2004).;Cooking loss of meat samples was determined so that He et al (2015) and Kim et al (1995) described.;Shear force values of cooked samples were determined using texture analyzer with WarnerBratzler shear apparatus, while muscular fibers were almost parallel to the force as normally occurs during chewing. Six meat cores (1.27 cm diameter) parallel to muscle fiber were sheared once through the center by a warnerBratzler shear attachment using 50 kg compression load cell and 200 mm/min crosshead speed (Karimi et al., 2008; Hosseini et al., 2012).;After 24 and 48 h marination, samples were prepared for (SEM) as described by Naveena et al (2004).;A completely randomized design in a factorial experiment with 3 replications was employed by using analysis of variance (ANOVA) to study the effect of ultrasonication, and time on the physicochemical properties of camel meat. Least significant difference (LSD) test was used to determine differences between treatments means (P lt;0.05). Data were analyzed using the procedure of SAS version 8 (Burke et al., 2003).; ;Results and discussion: Ultrasonication caused a decrease in pH while increasing marination time caused an increase in pH of all samples compared with control. Cooked samples showed higher pH compering with raw marinated samples. Ultration and increasing marination time caused a significant increase in marinade uptake due to structural changes. Application of ultrasound, the higher concentration of acid in marinade solution and longer marination period resulted in lower shear forces of meat samples.;Marination by 30% GE in addition to 1.5% citric acid and ultration illustrated maximum tenderness, lower pH and L*value but caused less water holding capacity and higher cooking loss.;