Dry fruit as source of fungal contaminants or functional compounds?

Abstract This study evaluated the role of dry fruits as a source of fungal contaminants or functional compounds. Dry apple, apricot, candied fruits, prune, and white and black raisin were evaluated regarding patulin and ergosterol content, centesimal composition, pH, acidity, pectin, and phenolic profile. The ergosterol was detected in 38% of the samples and patulin (PAT) in 89%, the apricot samples stood out most by contaminant level. Apricot, candied fruit, and prunes presented moisture values beyond the other dry fruits. The pH ranged from 3.8 to 4.6; acidity from 0.1 to 1.0%; sugar content from 1.7 to 5.5%; and levels of soluble and insoluble pectin from 1.6 to 5.1% and 10.9% to 27.3%, respectively. The apples showed a higher content of free phenolic compounds (6.6 mg of gallic acid/g) with a predominance of gallic and protocatechuic acids. Pearson's correlation showed a significant positive correlation between patulin and ergosterol content (0.99) and soluble pectin (0.78); a significant negative relation between total sugars (-0.66) and free phenolic compounds (-0.63). Fungal contamination and the occurrence of PAT show that this mycotoxin is present and, therefore, the evaluation of fungal toxins in dry fruits is recommended before claiming them to be a source of functional compounds.

摘要 本研究评估了干果作为真菌污染物或功能性化合物来源的应用潜力。研究针对干燥苹果、杏、蜜饯果脯、西梅以及白葡萄干和黑葡萄干，检测了展青霉素（patulin, PAT）、麦角固醇（ergosterol）含量，样品的百分组成、pH值、酸度、果胶含量以及酚类物质组成。检测结果显示，38%的样品中检出麦角固醇，89%的样品中检出展青霉素（PAT），其中杏样品的污染物水平最为突出。杏、蜜饯果脯与西梅的水分含量高于其余干果样品。本次检测的样品pH值范围为3.8至4.6，酸度范围为0.1%至1.0%，总糖含量范围为1.7%至5.5%，可溶性果胶与不溶性果胶含量范围分别为1.6%至5.1%与10.9%至27.3%。干燥苹果的游离酚类化合物含量更高，达6.6 mg没食子酸/g，其酚类成分以没食子酸与原儿茶酸为主。皮尔逊相关性分析显示，展青霉素与麦角固醇含量（0.99）、可溶性果胶含量（0.78）之间存在显著正相关；而与总糖含量（-0.66）及游离酚类化合物含量（-0.63）之间存在显著负相关。真菌污染与展青霉素的检出情况表明，该真菌毒素普遍存在于干果中，因此在宣称干果为功能性化合物来源之前，建议先对其所含真菌毒素进行系统性评估。