Shiekh Khursheed Ahmad, Luanglaor Thitirat, Hanprerakriengkrai Natchaya, Jafari Saeid, Kijpatanasilp Isaya, Asadatorn Nicha, Worobo Randy W, Bekhit Alaa El-Din Ahmed, Assatarakul Kitipong
Department of Food Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
School of Agro-Industry, Mae Fah Luang University, Thasud, Chiang Rai 57100, Thailand.
Foods. 2023 Jan 6;12(2):277. doi: 10.3390/foods12020277.
Purple corn kernels were subjected to boiling and steaming times of 5-15 min to extract purple corn milk (PCM). Pasteurized and unpasteurized PCM samples were investigated for changes in anthocyanins, antioxidants, and physicochemical properties. Anthocyanins, total phenolics, antioxidant activity, color and viscosity values showed promising results in pasteurized PCM samples extracted from kernels steamed for 5 min (PPCM-S5) compared to other samples ( ≤ 0.05). Changes in L*, a* and b* values, total phenolics and DPPH activity were lowered in PPCM-S5 samples with higher retention of anthocyanins compared to the PCM extracted from boiled kernels ( ≤ 0.05). PCM extracted from 5 min steamed kernels fortified with 4% sucrose (PCM5-S4) after pasteurization revealed the lowest changes in color, pH, total soluble solid and viscosity during 12 days of storage at 4 °C compared to the unpasteurized PCM without sucrose and pasteurized PCM fortified with 6% sucrose. Additionally, pasteurized PCM5-S4 samples marked the highest anthocyanins, total phenolics and antioxidant activity during storage. Microbial load was lowest in pasteurized PCM5-S4 samples stored at 4 °C for 12 days. However, coliforms, yeast or mold and were not present in the thermally processed PCM samples. The highest sensory scores were obtained in PCM5-S4 at day 12 of storage compared to PCM without any treatment. Therefore, pasteurized PCM extracted from 5 min steamed purple corn kernels retained bioactivity along with 4% sucrose fortification resulted in higher sensory acceptability. As a consequence the shelf-life of PCM5-S4 sample was extended up to 12 days at 4 °C.
将紫色玉米粒进行5 - 15分钟的煮沸和蒸煮，以提取紫玉米奶（PCM）。对巴氏杀菌和未巴氏杀菌的PCM样品进行花青素、抗氧化剂和理化性质变化的研究。与其他样品相比（≤0.05），从蒸煮5分钟的玉米粒中提取的巴氏杀菌PCM样品（PPCM - S5）中的花青素、总酚、抗氧化活性、颜色和粘度值显示出良好的结果。与从煮沸的玉米粒中提取的PCM相比，PPCM - S5样品中L*、a和b值、总酚和DPPH活性的变化较低，花青素保留率较高（≤0.05）。巴氏杀菌后，用4%蔗糖强化的从蒸煮5分钟的玉米粒中提取的PCM（PCM5 - S4），与未添加蔗糖的未巴氏杀菌PCM和添加6%蔗糖的巴氏杀菌PCM相比，在4℃储存12天期间，颜色、pH值、总可溶性固形物和粘度的变化最小。此外，巴氏杀菌的PCM5 - S4样品在储存期间的花青素、总酚和抗氧化活性最高。在4℃储存12天的巴氏杀菌PCM5 - S4样品中的微生物负荷最低。然而，热加工的PCM样品中不存在大肠菌群、酵母或霉菌。与未经任何处理的PCM相比，PCM5 - S4在储存第12天获得了最高的感官评分。因此，从蒸煮5分钟的紫色玉米粒中提取的巴氏杀菌PCM，在添加4%蔗糖强化的情况下，保留了生物活性，导致更高的感官可接受性。因此，PCM5 - S4样品在4℃下的保质期延长至12天。
