پديد آورندگان :
سرداري فر، آيمن دانشگاه آزاد اسلامي واحد تبريز - گروه علوم و صنايع غذايي، تبريز، ايران , الماسي، هادي دانشگاه اروميه - دانشكده كشاورزي - گروه علوم و صنايع غذايي، اروميه، ايران , روفه گري نژاد، ليلا دانشگاه آزاد اسلامي واحد تبريز - گروه علوم و صنايع غذايي، تبريز، ايران
كليدواژه :
آب سيب , غني سازي , روي , درون پوشاني , خواص فيزيكي‌شيميايي
چكيده فارسي :
زمينه مطالعاتي: غني سازي مواد غذايي يكي از روش‌هاي تأمين كمبود ريزمغذي‌ها براي اقشار مختلف مردم محسوب مي‌شود. هدف: هدف از اين پژوهش، توليد آب سيب غني شده با روي به‌عنوان يك محصول فراسودمند و غني شده‌ي جديد بود. روش كار: براي اين منظور، سولفات روي با پكتين و صمغ عربي به نسبت 1 به 10 و با استفاده از روش خشك كردن پاششي درون پوشاني شد و آزمون‌هاي تعيين اندازه ذرات و پتانسيل زتا و ميكروسكوپ SEM بر روي نمونه‌هاي پودر انجام شد. در مرحله دوم، ميكروكپسول‌هاي توليد شده و همچنين سولفات روي به شكل آزاد، به ميزان 2/5 ميلي گرم بر ليتر به فرمولاسيون آب سيب اضافه شدند و در طي مدت 60 روز نگهداري در دماي يخچال، تأثير آنها بر روي خواص فيزيكوشيميايي و حسي آبميوه مطالعه شد. نتايج: بررسي خواص ميكروكپسول‌ها نشان داد كه اندازه ذرات كپسول‌هاي پايدار شده با پكتين (nm 430) كمتر از صمغ عربي (nm 760) و مي‌باشد. تصاوير ميكروسكوپ SEM توزيع يكنواخت اندازه ذرات در هر دو نوع ميكروكپسول را نشان داد. افزودن ميكروكپسول يا روي آزاد، تأثير قابل توجهي بر روي pH، اسيديته و انديس فرمالين آب سيب ندارد. با افزودن ميكروكپسول‌ها، كدورت آب سيب افزايش يافت. تأثير ميكروكپسول پايدار شده با صمغ عربي بر روي كدورت بيشتر از پكتين بود. ميكروكپسول صمغ عربي – روي، باعث بهبود شاخص رنگ آب سيب شد. افزودن ميكروكپسول‌ها همچنين ويسكوزيته آبميوه را افزايش داد كه تأثير صمغ عربي در روي اين ويژگي نيز بيشتر از پكتين بود. غني سازي آبميوه با ميكروكپسول‌ها، شمارش باكتري‌هاي سرمادوست را در طول نگهداري اندكي افزايش داد. همچنين ميزان پذيرش كلي نمونه‌هاي آب سيب در حالت استفاده از ميكروكپسول‌ها، تفاوت معني داري با نمونه شاهد نداشت. نتيجه گيري نهايي: در كل نتايج نشان داد كه با افزودن ميكروكپسول‌هاي حاوي سولفات روي به آب سيب مي‌توان يك محصول غني شده جديد توليد نمود بدون اينكه در خواص فيزيكوشيميايي آن تغيير قابل توجهي ايجاد شود.
چكيده لاتين :
Introduction: Fortification is an efficient method for supplying of nutrient deficiency in society. Zinc is one of the main micronutrients that its deficiency in the Iranian people has been approved. This element has many important roles in body metabolisms such cell proliferation, control of growth, improving of immunological system, growth of nail, hair, bones, etc (Zlewski 1996). Fruit juice is a most popular beverage between children and adults and its fortification with zinc element can be a good criteria for compensate of its deficiency (Villalpando et al., 2006). The aim of this research was to produce apple juice fortified with zinc as a new functional and fortified food. Introducing of a novel fortified beverage for supplying of zinc element can open a new insight of the production of fortified foods and beverages.
Materials and methods: Zinc sulphate was encapsulated with pectin and gum Arabic at ratio of 1:10 by spray drying method. Drying was applied at 180 ºC and the obtained powders were stored at refrigeration temperature. The particle size and zeta potential of microcapsules were analyzed by DLS test and SEM microscopy was utilized to study the morphological characteristics of microcapsules (Hosseinnia et al., 2017). At the second step, the produced microcapsules and also free zinc sulphate were added to the apple juice at concentration of 2.5 mg/L. This concentration was selected according to the ADI (acceptable daily intake) value of zinc. The physicochemical properties including pH, acidity, turbidity, color, formalin index and viscosity were investigated. The microbial properties and also sensorial characteristics of the fortified apple juice samples were also evaluated during 60 days storage at refrigerator temperature. One-way ANOVA and Duncan test were used for statistical analysis of obtained data.
Results and discussion: Studying of the morphology of microcapsules revealed that size of capsules produced with pectin (430 nm) is smaller than gum Arabic (760 nm) stabilized capsules and its surface charge is higher. The Zeta potential of gum Arabic stabilized microcapsules was -18 meV but it was equal to -28.6 meV for pectin stabilized samples, revealing the higher stability of pectin microcapsules in comparison to gum Arabic. The SEM images indicated that the homogenous microcapsules are produced by both of biopolymers but the uniform dispersion of pectin microcapsules was higher than gum Arabic. Results of the apple juice fortification indicated that the addition of microcapsules or free zinc had no significant effect on pH, acidity and formalin index of apple juice. These parameters were in the standard range of fruit beverages. This is an important factor for a fortified food that its characteristics are similar to the pure and non-fortified food (Younas et al., 2014). Effect of gum Arabic stabilized microcapsules on turbidity of apple juice was more than pectin-zinc microcapsules. Higher molecular weight and lower purity of gum Arabic in comparison to pectin was the reasons of this observation. On the other hand, gum Arabic enhanced the color index of apple juice but pectin had no effect. Addition of microcapsules increased the viscosity of juice and the effect of gum Arabic was more than pectin. Fortification of apple juice with microcapsules increased the psychrophilic counts during storage. This observation can be attributed to the cross contamination of microcapsules during production and storage of them. However, by a good heat processing of apple juice after fortification, this problem can be resolved. Also, the total acceptance of apple juice samples containing microcapsules had no significant difference with control sample. At 60th day of storage the sample fortified with pectin stabilized microcapsules had the highest total acceptance storage. The consumer acceptability is the most important factor for designing of fortified foods. Because the fortification can adversely affect the acceptance of fortified food or beverage by consumers (Das and Green 2016).
Conclusion: This research revealed that the encapsulation of zinc with gum Arabic and pectin biopolymers is possible and these microcapsules had acceptable characteristics for using in food fortification. But the efficiency of pectin was more than gum Arabic and it was suggested as the best candidate for production of zinc microcapsules with spray drying method. The spry drying method was proposed as a suitable method for production of zinc loaded microcapsules by both of biopolymers. According to the results of the second stage, fortification of apple juice with zinc microcapsules had no significant effect on the most of physical and chemical properties of beverage and thus the fabricated microcapsules can be used in food and beverage fortification. Generally, the results indicated that a new fortified product could be produced by incorporation of zinc coated microcapsules to apple juice without any altering in its physicochemical properties. The lower changes in the physicochemical characteristics of apple juice after incorporation of zinc microcapsules was the best achievement of this research. This product can be proposed to food and beverage companies as a new fortified product for zinc supplying and increasing of the absorption of this element with consumers. However, it should be noted that a comprehensive research is required for determining the bioavailability of zinc micronutrient in the fortified beverages and in the different consumers regarding their age and gender. Further studies on the bioavailability of encapsulated zinc and its release profile in gastrointestinal simulants are suggested to complete this research.
