Tagrida Mohamed, Benjakul Soottawat
International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
J Food Biochem. 2020 Dec;44(12):e13508. doi: 10.1111/jfbc.13508. Epub 2020 Oct 5.
Sedimentation process was used to remove chlorophyll from betel leaf ethanolic extracts (BLEE) and chaphlu leaf ethanolic extracts (CLEE). The influence of water quantity on chlorophyll content, total phenolic content (TPC), and antioxidant activity of the extracts was studied. The sedimentation process showed a remarkable reduction in chlorophyll A, chlorophyll B, and total chlorophyll contents of both extracts. Nevertheless, no differences in chlorophyll content, TPC, and antioxidant activities were observed between dechlorophyllized fractions in both extracts (p > .05). Liquid Chromatography-Mass Spectrometry (LC/MS) profiling showed that the BLEE dechlorophyllized using the extract/water ratio of 1:1 (BLEE-DC1) had higher phenolic compounds than CLEE-DC1. Isovitexin was the most abundant compound identified in the BLEE-DC1 while vitexin 4'-O-galactoside was the most prevalent in CLEE-DC1. When thermal and pH stabilities of the dechlorophyllized extracts were tested, BLEE-DC1 exhibited more heat stability (at 60-100°C for 0-60 min) than CLEE-DC1. Both dechlorophyllized extracts showed optimum antioxidant activities at pH 5.0. PRACTICAL APPLICATIONS: Oxidation process is associated with the numerous human diseases as well as it induces the deteriorative changes in foods, especially those rich in fat or lipid containing high polyunsaturated fatty acids. Numerous synthetic antioxidants have been employed but they may not be safe. Natural antioxidants have gained attention, particularly those from several leaves rich in polyphenols. However, due to the green color caused by chlorophylls, the extract is limited for further applications. Betel leaf ethanolic extract possessing high antioxidant activity could be dechlorophyllized using sedimentation process with the appropriate proportion of water. This green process not only showed the effective removal of chlorophyll, but also increased the proportion of polyphenol in the extract. Greenless betel leaf extract with augmented antioxidant activity can be used as natural additive to replace synthetic counterpart.
采用沉降法去除槟榔叶乙醇提取物(BLEE)和查夫鲁叶乙醇提取物(CLEE)中的叶绿素。研究了加水量对提取物叶绿素含量、总酚含量(TPC)和抗氧化活性的影响。沉降过程使两种提取物中的叶绿素A、叶绿素B和总叶绿素含量显著降低。然而,两种提取物的脱叶绿素组分在叶绿素含量、TPC和抗氧化活性方面均未观察到差异(p>0.05)。液相色谱-质谱联用(LC/MS)分析表明,提取物/水比例为1:1脱叶绿素的BLEE(BLEE-DC1)比CLEE-DC1含有更多的酚类化合物。异荭草苷是BLEE-DC1中鉴定出的最丰富的化合物,而牡荆素4'-O-半乳糖苷在CLEE-DC1中最为普遍。在测试脱叶绿素提取物的热稳定性和pH稳定性时,BLEE-DC1比CLEE-DC1表现出更高的热稳定性(在60-100°C下处理0-60分钟)。两种脱叶绿素提取物在pH 5.0时均表现出最佳抗氧化活性。实际应用:氧化过程与多种人类疾病相关,同时它会导致食品发生变质变化,尤其是那些富含脂肪或含有高多不饱和脂肪酸的脂质食品。人们使用了许多合成抗氧化剂,但它们可能不安全。天然抗氧化剂受到了关注,特别是那些来自富含多酚的几种叶子的抗氧化剂。然而,由于叶绿素导致的绿色,提取物在进一步应用中受到限制。具有高抗氧化活性的槟榔叶乙醇提取物可以通过沉降法与适当比例的水进行脱叶绿素处理。这种绿色工艺不仅有效地去除了叶绿素,还增加了提取物中多酚的比例。具有增强抗氧化活性的无绿色槟榔叶提取物可作为天然添加剂替代合成添加剂。