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. K E Y W O R D S antioxidant activities, betel leaf extract, chaphlu leaf extract, chlorophyll removal, LC/MS, sedimentation | 3 of 14 TAGRIDA AnD BEnJAKUL were thoroughly washed with tap water and dried in a hot air oven at 50°C overnight until moisture content of the leaves was less than 10%. Dried samples were blended, and then, sieved using 80 mesh stainless-steel sieve. The obtained powder named as "betel leaf
Betel leaf ethanolic extract dechlorophyllized using sedimentation (BLEE-SED) exhibited enhanced antioxidant and antibacterial activities. BLEE-SED could extend the shelf-life of Nile tilapia fillets during refrigerated storage (4 °C) up to 9 days.
Betel leaf ethanolic extract (BLEE), which was dechlorophyllized by sedimentation process was loaded in liposomes at 1 and 2% (w/v) concentrations using two different methods, namely thin film hydration (TF) and ethanol injection (EI) methods. Liposomes loaded with 1% BLEE and prepared by TF method (BLEE/L‐T1) had the smallest particle size and paler color than BLEE/L‐E1, BLEE/L‐E2, and BLEE/L‐T2 (p < .05). BLEE/L‐T1 also showed strong stability as judged by its lowest zeta potential and polydispersity index. The highest encapsulation efficiency (EE) and lowest releasing efficiency (RE) were also found with BLEE/L‐T1. No significant difference (p > .05) in the antioxidant activities was detected between the BLEE‐loaded liposomes and BLEE solutions, indicating that encapsulation had no adverse effect on BLEE antioxidant potency. BLEE/L‐T1 showed higher antioxidant stability than unencapsulated BLEE at the equivalent amount based on EE (BLEE/U‐T1) during in vitro gastrointestinal tract digestion system. Therefore, BLEE/L‐T1 could be an efficient delivery system for improving stability of antioxidant activities of BLEE.
Practical applications
Despite the many benefits of betel leaf ethanolic extract, it still has some distinctive odor and slightly greenish color as well as instability induced by environment factors, which can limit applications in foods. Encapsulation of the betel extract in liposomes can be a good approach to mask its undesirable color and odor and to augment its antioxidant stability. Liposomal technology can be used to load betel leaf extract. However, different methods have been implemented to prepare liposomes that exhibit varying encapsulation efficacy as well as bioactivities. Thin film hydration method was shown to yield the liposome with better physical characteristics, higher encapsulation efficiency, slower release, and higher antioxidant stability than the ethanol injection method. Therefore, the thin film hydration method could be adopted to prepare stable liposomes loaded with betel leaf extract that possess antioxidant activity suitable for food applications.
Fish is perishable and has the short shelf‐life. To maintain its quality, it is necessary to implement the appropriate technology, particularly nonthermal processing along with safe additive, especially from plant origin under the concept of "hurdle technology". The use of potential vesicle including liposome for loading the plant extract could be a means to enhance the stability and activities of the extract. The current study aimed to evaluate the effect of liposomes loaded with betel leaf ethanolic extract (L/BLEEs) or unencapsulated BLEE (U/BLEE) in conjunction with modified atmospheric packaging (MAP) and nonthermal plasma (NTP) on the quality changes and shelf‐life of Nile tilapia fillets (TFs) stored under refrigerated condition (4°C). TFs treated with L/BLEE or U/BLEE at 400 ppm, packed under modified atmosphere (CO2:Ar:O2 = 60:30:10) and subjected to NTP for 300 s (L/BLEE‐400/MAP‐NTP and U/BLEE‐400/MAP‐NTP, respectively) had the lowest microbial and chemical changes during storage, while the control showed the highest changes (p < 0.05). Lipid oxidation was lower in these samples, ascertained by more retained polyunsaturated fatty acids and lower lipid oxidation based on Fourier transform infrared (FT‐IR) spectra. Overall likeness scores were similar (p > 0.05) between all the samples at day 0 of storage. Only L/BLEE‐400/MAP‐NTP and U/BLEE‐400/MAP‐NTP were still sensorially acceptable after 12 days at 4°C. Therefore, L/BLEE or U/BLEE combined with MAP/NTP treatment could be adopted as a potent hurdle for shelf‐life extension of TFs.
Practical Application
Natural additives and nonthermal processing technologies have gained increasing interest for preservation of fish. Liposomes loaded with betel leaf ethanolic extract (L/BLEE) rich in polyphenolics could be used together with modified atmospheric packaging (MAP) and nonthermal plasma (NTP) to retard bacterial growth and chemical deterioration in Nile tilapia fillets. These hurdles were proven to be able to maintain the qualities of tilapia fillets stored at 4°C up to 12 days, especially when L/BLEE was used at 400 ppm. Therefore, shelf‐life extension of Nile tilapia fillets or other fish can be achieved by using the natural additive and nonthermal processing technologies.
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