Moisture adsorption isotherms and storability of dried hazelnut inshells and kernels produced in Oregon were evaluated and compared among cultivars, including Barcelona, Yamhill, and Jefferson. Experimental moisture adsorption data fitted to Guggenheim-Anderson-de Boer (GAB) model, showing less hygroscopic properties in Yamhill than other cultivars of inshells and kernels due to lower content of carbohydrate and protein, but higher content of fat. The safe levels of moisture content (MC, dry basis) of dried inshells and kernels for reaching kernel water activity (aw ) ≤0.65 were estimated using the GAB model as 11.3% and 5.0% for Barcelona, 9.4% and 4.2% for Yamhill, and 10.7% and 4.9% for Jefferson, respectively. Storage conditions (2 °C at 85% to 95% relative humidity [RH], 10 °C at 65% to 75% RH, and 27 °C at 35% to 45% RH), times (0, 4, 8, or 12 mo), and packaging methods (atmosphere vs. vacuum) affected MC, aw , bioactive compounds, lipid oxidation, and enzyme activity of dried hazelnut inshells or kernels. For inshells packaged at woven polypropylene bag, MC and aw of inshells and kernels (inside shells) increased at 2 and 10 °C, but decreased at 27 °C during storage. For kernels, lipid oxidation and polyphenol oxidase activity also increased with extended storage time (P < 0.05), and MC and aw of vacuum packaged samples were more stable during storage than those atmospherically packaged ones. Principal component analysis showed correlation of kernel qualities with storage condition, time, and packaging method. This study demonstrated that the ideal storage condition or packaging method varied among cultivars due to their different moisture adsorption and physicochemical and enzymatic stability during storage. PRACTICAL APPLICATION Moisture adsorption isotherm of hazelnut inshells and kernels is useful for predicting the storability of nuts. This study found that water adsorption and storability varied among the different cultivars of nuts, in which Yamhill was less hygroscopic than Barcelona and Jefferson, thus more stable during storage. For ensuring food safety and quality of nuts during storage, each cultivar of kernels should be dried to a certain level of MC. Lipid oxidation and enzyme activity of kernel could be increased with extended storage time. Vacuum packaging was recommended to kernels for reducing moisture adsorption during storage.

中文翻译：

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美国俄勒冈州生产的榛子壳和仁的水分吸附等温线和储存性

对产于俄勒冈州的干榛子壳和核的水分吸附等温线和储存性进行了评估，并在不同品种之间进行了比较，包括巴塞罗那、Yamhill 和 Jefferson。符合 Guggenheim-Anderson-de Boer (GAB) 模型的实验水分吸附数据显示，由于碳水化合物和蛋白质含量较低，但脂肪含量较高，Yamhill 的吸湿性低于其他带壳和内核品种。使用 GAB 模型估计，巴塞罗那干燥的带壳和内核的水分含量（MC，干基）的安全水平（MC，干基）达到内核水分活度 (aw) ≤0.65 为 11.3% 和 5.0%，Yamhill 为 9.4% 和 4.2%，杰斐逊分别为 10.7% 和 4.9%。储存条件（2 °C，85% 至 95% 相对湿度 [RH]，10 °C，65% 至 75% RH，27 °C，35% 至 45% RH），时间（0、4、8、或 12 个月），包装方法（大气与真空）影响干榛子壳或核的 MC、aw、生物活性化合物、脂质氧化和酶活性。对于用聚丙烯编织袋包装的内壳，内壳和仁（内壳）的 MC 和 aw 在 2 和 10 °C 时增加，但在 27 °C 时降低。对于籽粒，脂质氧化和多酚氧化酶活性也随着储存时间的延长而增加（P < 0.05），并且真空包装样品的MC和aw在储存过程中比常压包装样品更稳定。主成分分析表明籽粒品质与储存条件、时间和包装方法相关。本研究表明，不同品种的理想贮藏条件或包装方法因贮藏过程中吸湿性、物理化学和酶稳定性的不同而不同。实际应用 榛子壳和仁的水分吸附等温线可用于预测坚果的储存性。这项研究发现，不同品种的坚果吸水性和储存性不同，其中 Yamhill 的吸湿性低于 Barcelona 和 Jefferson，因此在储存过程中更稳定。为保证坚果在贮藏过程中的食品安全和质量，每个品种的核仁都应干燥至一定的MC水平。随着贮藏时间的延长，籽粒的脂质氧化和酶活性会增加。建议对谷粒进行真空包装，以减少储存过程中的水分吸收。