Comparison between near and far wavelength sections were evaluated in the infrared-assisted freeze-drying (IRFD) process of açai puree. Samples were dried using freeze drying (FD); near IRFD (NIRFD); far IRFD (FARFD); and infrared heating after 20% weight reduction, NIRFD_20%WR and FARFD_20%WR. IRFD significantly reduced the total drying time, with NIRFD and FARFD taking 49.42% and 33.40% less time than FD, respectively. The structure of powdered using IRFD was more open and with larger pores. FARFD_20%WR had collapsed cells that compromised the functional properties of the powder (wettability, dispersibility). As for bioactive compounds, phenolic content was not affected by IRFD, ranging from 963.44 to 1025.60 mg/100 g. Antioxidant capacity increased (59.91 to 88.06%) when far infrared was used due to a Maillard reaction that generated antioxidant compounds and darker product. Content of anthocyanins reduced in samples dried by far infrared. Overall, NIRFD was more efficient, as it reduced total drying time without compromising product quality.

Industrial relevance

The high-energy consumption of traditional freeze-drying limit the large-scale industrial production of freeze-dried açai puree. The infrared-assisted freeze-drying has been contributions on reducing drying energy consumption with time saving varying from 24.73 to 49.42% compared to the conventional freeze-drying treatment, maintaining the color, appearance and nutritional quality of the açai puree. Besides that, this study outstands that near wavelength lamps are more suitable for food drying by IRFD.

中文翻译：

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阿萨伊果泥的红外辅助冷冻干燥 (IRFD)：对干燥动力学、微观结构和生物活性化合物的影响

在阿萨伊果泥的红外辅助冷冻干燥 (IRFD) 过程中评估了近、远波长部分之间的比较。使用冷冻干燥 (FD) 干燥样品；近IRFD（NIRFD）；远红外线（FARFD）；和红外加热后减重_20%，NIRFD _20%WR和 FARFD _20%WR。IRFD 显着减少了总干燥时间，NIRFD 和 FARFD 的时间分别比 FD 少 49.42% 和 33.40%。使用 IRFD 的粉末结构更开放且具有更大的孔隙。FARFD _20%WR已经塌陷的细胞损害了粉末的功能特性（润湿性、分散性）。至于生物活性化合物，酚类含量不受 IRFD 影响，范围为 963.44 至 1025.60 mg/100 g。当使用远红外线时，抗氧化能力增加（59.91% 至 88.06%），这是由于美拉德反应产生了抗氧化化合物和更深的产物。远红外干燥样品中花青素含量降低。总的来说，NIRFD 效率更高，因为它在不影响产品质量的情况下减少了总干燥时间。

工业相关性

传统冷冻干燥的高能耗限制了冷冻干燥巴西莓果泥的大规模工业化生产。红外线辅助冷冻干燥有助于降低干燥能耗，与传统冷冻干燥处理相比，节省时间 24.73% 至 49.42%，保持了巴西莓果泥的颜色、外观和营养品质。除此之外，这项研究还表明，近波长灯更适合通过 IRFD 进行食品干燥。