Dept. of Food and Biotechnology, Facultad de Química, Univ. Nacional Autónoma de México., C.P, 04510, Mexico City, Mexico.
Dept. of Biological Systems, Universidad Autónoma Metropolitana-Xochimilco, Mexico City, Mexico.
J Food Sci. 2019 May;84(5):954-962. doi: 10.1111/1750-3841.14589. Epub 2019 Apr 17.
Pigmented maize has been extensively studied due to its high anthocyanin content. This study has been focused mainly on kernel, although the whole plant of purple corn is a potential source of anthocyanins. First, general parameters of extraction (solvent system, solvent-to-solid ratio, number of extractions, and acid type) were established depending on the total anthocyanins content. Then, three extraction methods to access anthocyanins were compared: maceration extraction (ME), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE). Since the residual material still possessed an intense color, a further treatment was performed by application of enzymatic-assisted extraction (EAE). Three enzymatic cocktails (Xylanases, Celluclast, and Depol), pH, and temperature were evaluated to establish optimal reaction conditions. Subsequent analysis and identification of the anthocyanins obtained by four different extraction techniques were performed using HPLC and HPLC-mass spectrometry, respectively. The most efficient method was UAE using 20 min of ultrasound (100 W) preceded by sample treatment in the following conditions: ethanol/water/lactic acid mixture (80:19:1), two extractions, 1:10 solvent-to-solid ratio. As a result, anthocyanins from corn cob and corn husk were extracted at concentrations of 24.32 and 25.80 mg/gDW, respectively. No difference in the anthocyanins profile for samples extracted by three different methods was observed. However, an enhanced presence of cyanidin-3-(6''malonyl)glucoside was detected in the sample corresponding to the EAE method. Therefore, the Cahuacintle corn husk can be considered as a competitive source of anthocyanins with the available commercial sources. PRACTICAL APPLICATION: The by-products obtained from Cacahuacintle purple corn can be potentially used as natural colorants thanks to their anthocyanins content. In this work, we established the most efficient extraction method of anthocyanins from corn husk and corn cob, and demonstrated that their anthocyanins profile is comparable to other Peruvian purple corns, which are currently used as natural colorants. Therefore, the extraction procedure described in this study might be scaled-up in an industrial process to get access to anthocyanins from undervalued wastes.
由于其高花青素含量，已对有色玉米进行了广泛研究。这项研究主要集中在玉米的玉米粒上，尽管紫玉米的整株植物都是花青素的潜在来源。首先，根据总花青素含量确定了一般提取参数（溶剂体系、溶剂与固体的比例、提取次数和酸类型）。然后，比较了三种提取花青素的方法：浸渍提取（ME）、超声辅助提取（UAE）和微波辅助提取（MAE）。由于残余材料仍具有强烈的颜色，因此通过应用酶辅助提取（EAE）进行了进一步处理。评估了三种酶混合物（木聚糖酶、纤维素酶和Depol）、pH 值和温度，以确定最佳反应条件。然后使用高效液相色谱法（HPLC）和高效液相色谱-质谱法（HPLC-MS）分别对通过四种不同提取技术获得的花青素进行分析和鉴定。最有效的方法是使用 100 W 超声预处理 20 分钟的 UAE，然后在以下条件下进行样品处理：乙醇/水/乳酸混合物（80:19:1），两次提取，溶剂与固体比为 1:10。结果，从玉米芯和玉米皮中提取的花青素浓度分别为 24.32 和 25.80mg/gDW。用三种不同方法提取的样品的花青素谱没有差异。然而，在 EAE 方法对应的样品中检测到了花青素-3-（6''-丙二酰基）葡萄糖苷的含量增加。因此，Cahuacintle 玉米皮可以被认为是一种有竞争力的花青素来源，与现有的商业来源相当。实际应用：由于其花青素含量，Cacahuacintle 紫玉米的副产物可潜在用作天然着色剂。在这项工作中，我们建立了从玉米皮和玉米芯中提取花青素的最有效方法，并证明了它们的花青素谱与其他秘鲁紫玉米相当，这些紫玉米目前被用作天然着色剂。因此，本研究中描述的提取程序可以在工业过程中扩大规模，以从被低估的废物中获得花青素。
