ارزیابی ویژگی های فیزیکی میوه، متابولیت های ثانویه و شاخص قهوه ای شدن ژنوتیپ سیب توسرخ بکران و برخی ارقام سیب بهاره

به منظور مقایسه کیفیت سیب توسرخ بکران و برخی سیب‌های بهاره ایران، میوه‌های ژنوتیپ سیب توسرخ بکران از روستای بکران در شهرستان شاهرود و چند رقم سیب بهاره در مرحله رسیدن میوه از ایستگاه تحقیقاتی گلمکان شهرستان مشهد تهیه شدند. ویژگی‌های فیزیکی میوه شامل وزن تر، سفتی، وزن حجمی و ویژگی‌های شیمیایی شامل اسیدیته، اسید کل، مواد جامد محلول، شاخص طعم، میزان آنتوسیانین، محتوای فنل کل، فلاونوئید کل، قدرت ضد اکسایشی و همچنین شاخص قهوه‌ای شدن آنزیمی بافت میوه در ارقام انتخابی اندازه‌گیری شد. بیشترین مقدار قهوه‌ای شدن آنزیمی در سیب په‌پن و کمترین مقدار در سیب توسرخ بکران مشاهده شد. نتایج تجزیه واریانس داده‌ها نشان داد که بیشترین مقدار مواد جامد محلول در ژنوتیپ سیب توسرخ بکران (25 درجه بریکس) و کمترین مقدار در رقم گلاب صحنه (11.4 درجه بریکس) بود. بیشترین مقدار شاخص طعم میوه (ta/tss) در ارقام په‌پن، گلاب صحنه، و گلاب کهنز و کمترین مقدار در ژنوتیپ سیب توسرخ بکران (8.38) مشاهده شد. کمترین مقدار اسیدیته (2.98) در ژنوتیپ توسرخ بکران و بیشترین مقدار (4.61) در رقم گلاب کهنز مشاهده شدند. بیشترین مقدار آنتوسیانین در سیب توسرخ بکران (88.50) و کمترین مقدار در رقم گلاب صحنه (8.44) یافت شد. نتایج تجزیه واریانس داده‌ها نشان داد که بیشترین قدرت ضد اکسایشی مربوط به سیب توسرخ بکران (93.73 درصد) بود. سیب توسرخ بکران با دارا بودن بیشترین مقدار مواد جامد محلول، بیشترین مقدار آنتوسیانین و فلاونوئید و بیشترین قدرت ضداکسایشی و دارا بودن طعمی مطلوب و ظاهری متمایز می تواند به عنوان یک میوه کاملاً بومی با مصارف تازه خوری و جهت تولید فراورده های مختلف مورد توجه قرار گیرد.

Investigation of Correlation of Enzymatic Browning fruit tissue and Amount of Phenolic Compounds, Flavonoid, and Anthocyanin Red-flash and Some Iranian Spring Apple Cultivars

Introduction Apple is one of the most important horticultural crops in Iran. The aim of this study was to investigate the effect of genotype on physical and chemical properties of fruit; to evaluate the amount of fruit secondary metabolites and correlation between them with the enzymatic browning in some Iranian apple cultivars. Recently redfleshed apples have been attracted the attention of many researchers and fruit marketers because the flesh of those cultivars contains a high amount of red pigment anthocyanins, which show strong antioxidant activity. These cultivars have a better place in the market for the consumers because of the attractiveness, quality and high levels of anthocyanins and other phenolic compounds in fruits. Development of such new varieties with unique properties is important for improving the apple breeding and processing industry in the world. Phenolic compounds and flavonoids are products of the phenylpropanoid pathway. They are secondary metabolites and are responsible for different functions in the plant life cycle. Secondary metabolites play an important role in the quality of food (color, flavor, and odor). Also production of secondary metabolites may be a part of the plant defense system.;Materials and Methods The fruits of ‘MorabaeeMashhad’, ‘Top Red Delicious’, ‘Golab Kohanz’, ‘Winter Banana’, ‘Golabe Kermanshah’, ‘Early Devan’ and ‘Pepin’ apple cultivars were harvested manually from trees at commercial maturity stage in Mashhad city, and ‘Redflash’ apple cultivar was harvested in Shahrood city (Bekran Village), Iran. Fruits were transported to the laboratory soon after harvest. The measured chemical properties were consisted of total soluble solids (TSS), titrable acidity (TA), TSS: TA, total phenol content (TPC) and Antioxidant. Titratable acidity (TA) was determined by Korean models GMK855 and reported g 100 g1 of malic acid. Total soluble solids (TSS) was determined at 20 ◦C with a refractometer and reported as ◦Brix. The pH value of fruit was measured with a pH meter at 20◦C. The pH differential method was used to determine the total anthocyanin content. The absorbance of the solution was measured at 510 nm. The total phenolic content was determined by a modified FolinCiocalteu reagent method. This experiment was conducted according to the completely randomized design; with thirty replicates. Data were analyzed statistically by SPSS statistical software and differences among means were determined for significance at p lt; 0.05 using Duncan’s multiple range test.;Results and Discussion The highest and lowest of enzymatic browning was found in ‘Pepin’ and Redflash apple cultivars, respectively. Red Delicious, Macintosh, and Liberty showed high levels of enzymatic browning. According to some researchers, there is a strong correlation between the amount of browning and total phenol content of apple varieties Empire , Rome , Golden Delicious and Delicious (oseteng and Lee 1987; Milani and Hamedi 2005). San et al. (2002) revealed that there was a direct correlation between fruit phenolic content and antioxidant activity in 11 fruit species, indicating a significant contribution of phenolic compounds in the antioxidant activity of fruits. The results showed that the effect of cultivar on physicchemical properties of fruit was significant at 5% probability level. The concentration of total soluble solids was significantly affected by cultivar, the highest concentration of total soluble solids was observed for Redflesh apple cultivar while the lowest was recorded in Golabe Kermanshah. Redflesh and Golabe Kermanshah cultivars had the highest and the lowest anthocyanin contents andthe highest and lowest of pH values were observed in Redflesh and Golab Kohanz cultivars, respectively. The highest concentration of total phenolics was observed for MorabaeeMashhad while the lowest was seen in Early Devan cultivars. The correlation between the enzymatic browning and antioxidant capacity of fruits was 0.507*.;Conclusions The present research confirms that Redflesh apple cultivar as a native fruit has been of interest to researchers and consumers because of its high amount of soluble solids, anthocyanins and flavonoids content, high level of antioxidant capacity and having a specific flavor and taste. Therefore, it can be a worthy cultivar for apple breeding programs and development in future.