Şahin Sümeyye, Aydın Yeşim
Department of Food Engineering, Faculty of Agriculture, Ordu University, Ordu, Türkiye.
Department of Food Engineering, Institute of Science, Ordu University, Ordu, Türkiye.
J Food Sci. 2025 Jul;90(7):e70384. doi: 10.1111/1750-3841.70384.
Hazelnuts without skin are preferred by consumers. Traditionally, the skin is peeled off by the roasting technique (RT). However, RT causes undesirable reactions such as lipid oxidation. Therefore, pressurized water technique (PWT) was developed as an alternative hazelnut peeling method. In this study, the effect of PWT on quality parameters including chemical composition, ultrastructure, peroxide value (PV), free fatty acidity (FFA), total antioxidant capacity (TAC), total phenolic content (TPC), total aflatoxin content (AFC), and volatile compounds of hazelnut samples during long-term storage (12 months) was evaluated and compared with RT. Generally, FFA, TAC, AFC, and fatty acid contents in hazelnuts were not affected by peeling methods. Before storage, hazelnuts peeled by PWT exhibited slightly higher TPC and slightly lower protein and oil contents than hazelnuts peeled by RT. Additionally, no peroxide formation was detected in hazelnuts peeled by PWT before storage. Nevertheless, after storage, hazelnuts peeled by RT showed 8.2 times higher PV compared to hazelnuts peeled by PWT. Unlike hazelnuts peeled by PWT before storage, a total of 17 different volatile compounds, mostly lipid oxidation products, were detected in hazelnuts peeled by RT. Hexanal, an indicator for secondary oxidation, in hazelnuts peeled by RT before storage was determined to be 1.9 times higher than hazelnuts peeled by PWT. More burst oleosomes in microstructure of hazelnuts peeled by RT were observed by SEM. These results indicate that PWT demonstrated more oxidation stability and shelf-life quality in hazelnuts compared to RT. Therefore, among these peeling methods, PWT can be recommended for safe food production. PRACTICAL APPLICATION: While the roasting process is used to peel the hazelnut skin, lipid oxidation formation is inevitable during this process. Lipid oxidation products not only deteriorate the product quality but also pose a health risk. The newly developed, pressurized water peeling technique increases the lipid oxidation stability in hazelnuts. Increasing oxidation stability by the pressurized water peeling technique ensures that the quality of the hazelnut is preserved, and its shelf life is increased.
消费者更喜欢无皮榛子。传统上，通过烘烤技术（RT）去皮。然而，RT会引发诸如脂质氧化等不良反应。因此，开发了加压水技术（PWT）作为一种替代的榛子去皮方法。在本研究中，评估了PWT对长期储存（12个月）期间榛子样品的质量参数的影响，这些参数包括化学成分、超微结构、过氧化值（PV）、游离脂肪酸（FFA）、总抗氧化能力（TAC）、总酚含量（TPC）、总黄曲霉毒素含量（AFC）和挥发性化合物，并与RT进行了比较。一般来说，榛子中的FFA、TAC、AFC和脂肪酸含量不受去皮方法的影响。储存前，通过PWT去皮的榛子的TPC略高于通过RT去皮的榛子，而蛋白质和油含量略低。此外，储存前通过PWT去皮的榛子中未检测到过氧化物形成。然而，储存后，通过RT去皮的榛子的PV比通过PWT去皮的榛子高8.2倍。与储存前通过PWT去皮的榛子不同，通过RT去皮的榛子中总共检测到17种不同的挥发性化合物，其中大部分是脂质氧化产物。储存前通过RT去皮的榛子中作为二次氧化指标的己醛含量被确定为比通过PWT去皮的榛子高1.9倍。通过扫描电子显微镜观察到，通过RT去皮的榛子微观结构中有更多破裂的油体。这些结果表明，与RT相比，PWT在榛子中表现出更高的氧化稳定性和保质期质量。因此，在这些去皮方法中，PWT可推荐用于安全食品生产。实际应用：虽然烘烤过程用于去除榛子皮，但在此过程中脂质氧化的形成是不可避免的。脂质氧化产物不仅会降低产品质量，还会带来健康风险。新开发的加压水去皮技术提高了榛子中的脂质氧化稳定性。通过加压水去皮技术提高氧化稳定性可确保榛子的质量得以保存，并延长其保质期。
