Physicochemical, Phytochemical and Mycological Characteristics of Italia Muscat Raisins Obtained Using Different Pre-treatments and Drying Techniques

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• 作者：Hassène Zemni ; Arwa Sghaier ; Ramla Khiari ; Samir Chebil…
• 关键词：Italia Muscat grapes ; Raisins ; Drying ; Pre ; treatment ; Quality
• 刊名：Food and Bioprocess Technology
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：10
• 期：3
• 页码：479-490
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Food Science; Chemistry/Food Science, general; Agriculture; Biotechnology;
• 出版者：Springer US
• ISSN：1935-5149
• 卷排序：10

文摘

Raisins represent an economically important grapevine by-product. However, their quality is largely dependent on drying techniques and processing conditions. In this context, two drying processes were monitored: hot air drying in a convective oven and greenhouse drying. Grape berries were previously subjected to two chemical pre-treatments (olive oil and K₂CO₃ emulsion dipping (I) and NaOH solution bleaching (II)). Pre-treated grapes processed using both methods were compared with sun-dried samples. The results show that oven drying was more efficient and rapid (5 days) as compared with greenhouse drying (13 days). The end moisture content of grapes varied from 16.12% to 22.25% on a wet basis in dried samples, respectively. Significant differences in the pH value (3.85–4), acidity (1172.5–2730 mg TA/100 g DW) and total sugars (31.5–49.7%) were also observed, between raisin samples subjected to both treatments and drying methods, whereas protein levels (1–1.25%) were not affected. The analysis of minerals indicates that greenhouse-dried raisins had high amounts of calcium (Ca), magnesium (Mg) and sodium (Na). The highest polyphenol (417.70 mg GAE/100 g DW), flavonoid (115.87 mg CE/100 g DW) and tannin (368.13 mg CE/100 g DW) contents were recorded in sun-dried samples, respectively. The distribution of fungal flora shows a noteworthy variability among raisin samples, with a marked abundance of ochratoxinogenic species such as Aspergillus ochraceus and Aspergillus carbonarius (15.56% and 10.41%, respectively). Italia Muscat raisins processed using oven drying could be an economically interesting alternative to manage the excessive grapes production and consequently solve related marketing issues.