IMPACT OF SURFACE ACTIVE MINOR COMPONENTS ON PHYSICOCHEMICAL PROPERTIES OF ASSOCIATION COLLOIDS AND LIPID OXIDATION IN BULK OIL

Lipid oxidation is a great concern for food manufacturers and consumers as it negatively impacts not only food quality and nutritive values of food lipids, but also consumer health. Lipid oxidation in bulk oil is impacted by chemical factors, such as, prooxidants and antioxidants, and is also related to the existence of physical structures. Bulk oils contain a variety of surface active minor components which are able to form physical structures known as association colloids. These physical structures create oil-water interfaces which seem to be an important site where lipid oxidation occurs in bulk oil. Thus, this research focused on how the surface active minor components in bulk oil impact physical structure formation and oxidative stability in bulk oil. In the first study, the influence of polar lipid oxidation products isolated from used frying oil on the oxidative stability of bulk oils and oil-in-water (O/W) emulsions was investigated. Polar compounds were added to bulk stripped corn oil (with and without reverse micelles formed by dioleoylphosphatidylcholine, DOPC) and O/W emulsion to evaluate their prooxidative activity by following the formation of lipid hydroperoxides and hexanal. Polar compounds increased lipid oxidation in bulk oil with and without DOPC. The presence of DOPC reverse micelles decreased the prooxidant activity of the polar oxidation products. On the other hand, there was no significant effect of the polar compounds on oxidation of O/W emulsions. ix Besides phospholipids, other surface active minor components in commercial oils such as free fatty acids may impact lipid oxidation rates and the physical properties of association colloids. Thus, in the second study, the effects of free fatty acids on changes in the critical micelle concentration (CMC) of DOPC in stripped corn oil were determined by using the 7,7,8,8-tetracyanoquinodimethane (TCNQ) solubilization technique. Different free fatty acids including myristoleic, oleic, elaidic, linoleic and eicosenoic were added at 0.5% by wt along with the DOPC (1-2000 μmol/kg oil) into the bulk oils. There was no significant effect of free fatty acids with different chain length, configuration and number of double bonds on the CMC value for DOPC in bulk oil. However, increasing concentrations of oleic acid (0.5, 1, 3 and 5 % by wt) caused the CMC value for DOPC in bulk oils to increase from 400 to 1000 μmol/kg oil. Physical properties of DOPC reverse micelles in the presence of free fatty acids in bulk oils were also investigated by the small angle X-ray scattering technique. Results showed that free fatty acid could impact on the reverse micelle structure of DOPC in bulk oils. Moreover, free fatty acid decreased pH inside reverse micelle as confirmed by the NMR studies. The oxidation studies revealed that free fatty acids exhibited prooxidative activity in the presence and absence of DOPC. Different types of free fatty acids had similar prooxidative activity in bulk oil. In the last experiment, multiple surface active minor components including DOPC, dioleoylphosphatidylethanolamine (DOPE), oleic acid, diacylglycerols (DAG) and stigmasterol were incorporated to form nanostructures in stripped corn oil. Individual component significantly decreased the oil-water interfacial tension on which the DOPC and DOPE exhibited the strongest impact. However, the CMC study shows that only DOPC and DOPE could form aggregates at the CMC of 40 and 200 μmol/kg oil. The CMC of the mixed components was as low as 20 μmol/kg oil. The absence of a component did not significantly change the CMC value. x However, in the absence of DOPC, we were not able to observe the CMC of the mixed components in bulk oil. The NBD-PE probe was used to study the interfacial activity of minor components. The addition of mixed components caused the emission fluorescence intensity increase, suggesting that these components were at the oil-water interface. Again, the absence of a component from the mixture did not significantly change the fluorescence intensity, except when lacking of the DOPC. This indicates that the DOPC plays an important role on association colloid formation. The oxidation study showed that the association colloids formed by adding 100 μmol/kg oil of mixed components decreased the oxidative stability of bulk oil. In addition, the impact of mixed minor components at below (10 μmol/kg oil) and above their CMC (100 μmol/kg oil) on antioxidant activity of α-tocopherol and Trolox (water soluble derivative of tocopherols) at 10 and 50 μmol/kg oil was investigated. The addition of α-tocopherol and Trolox at 10 μmol/kg oil already compensated the prooxidant activity of association colloids. Trolox exhibited stronger antioxidant activity than α-tocopherol. However, the association colloids did not influence the antioxidative effectiveness of either α-tocopherol or Trolox in this study. In conclusion, the surface active minor components formed complex association colloids that decreased the oxidative stability of bulk oil. The presence of reverse micelle impacted the physical location of components such as polar lipid substrates, thus influenced their prooxidant activity. The physicochemical properties of association colloids could change according to the composition of minor components presenting at the oil-water interface. For example, the addition of free fatty acids extended the CMC and altered the pH of the water core of DOPC reverse micelles. The combination of multiple surface active components physically and chemically impacted the oxidative stability and activity of antioxidants in bulk oil. This research xi demonstrates what happens in real commercial oils which are complicated and could provide an idea of how to protect the oil from lipid oxidation

Utilization of Nongkhai Black Jasmine Rice Bran Oils for Development of Functional Drink Emulsion

Rice bran is a nutritious by-product from rice milling process. It is usually used as animal feed otherwise rejected as waste that could raise environmental issues. This research aims at utilizing oil extracted from Nongkhai black jasmine rice bran to develop an oil-in-water emulsion drink. Oil was extracted from Nongkhai black jasmine rice bran using hexane as a solvent by Soxhlet extraction method. Nongkhai black jasmine rice bran gave an oil yield of 12.38%. The extracted oil contained total phenolic 120.03 ± 1.26 g GAE/g oil, flavonoid 46.90 ± 0.69 g QE/g oil and a-oryzanol 236.73 ± 7.54 g/g oil. The antioxidant activity of the oil tested by DPPH, ABTS, and FRAP were 1676.63 ± 76.86, 592.75 ± 46.22, 1.31 ± 0.22 g Trolox equivalent/g oil, respectively. An oil-in-water emulsion beverage was then developed by dispersing 1% (w/w) of Nongkhai black jasmine rice bran oil with 0.1% (w/w) of Tween80/Span80 (1:1 w/w) as emulsifiers in water. The sweetness of the emulsion beverage was adjusted by adding erythritol mixed with stevia extract sweetener at 0.1, 0.2, 0.3, and 0.4 % (w/v). After pasteurization, all emulsion beverages were subjected to Just-about-right and 9-point hedonic sensory tests using a randomized complete block design. The emulsion containing 0.4 % sweetener had the highest overall liking score of 7.0 ± 1.1, representing moderate liking. The emulsion beverage contained -oryzanol 13.3 ± 0.3 g/mL with the antioxidant activity tested by ABTS of 267.0 ± 37.7 g Trolox equivalent/mL. In conclusion, Nongkhai black jasmine rice bran is a source of bioactive lipids that can be utilized as an ingredient in a plant-based functional drink emulsion

Utilization of Nongkhai Black Jasmine Rice Bran Oils for Development of Functional Drink Emulsion

Rice bran is a nutritious by-product from rice milling process. It is usually used as animal feed otherwise rejected as waste that could raise environmental issues. This research aims at utilizing oil extracted from Nongkhai black jasmine rice bran to develop an oil-in-water emulsion drink. Oil was extracted from Nongkhai black jasmine rice bran using hexane as a solvent by Soxhlet extraction method. Nongkhai black jasmine rice bran gave an oil yield of 12.38%. The extracted oil contained total phenolic 120.03 ± 1.26 g GAE/g oil, flavonoid 46.90 ± 0.69 g QE/g oil and a-oryzanol 236.73 ± 7.54 g/g oil. The antioxidant activity of the oil tested by DPPH, ABTS, and FRAP were 1676.63 ± 76.86, 592.75 ± 46.22, 1.31 ± 0.22 g Trolox equivalent/g oil, respectively. An oil-in-water emulsion beverage was then developed by dispersing 1% (w/w) of Nongkhai black jasmine rice bran oil with 0.1% (w/w) of Tween80/Span80 (1:1 w/w) as emulsifiers in water. The sweetness of the emulsion beverage was adjusted by adding erythritol mixed with stevia extract sweetener at 0.1, 0.2, 0.3, and 0.4 % (w/v). After pasteurization, all emulsion beverages were subjected to Just-about-right and 9-point hedonic sensory tests using a randomized complete block design. The emulsion containing 0.4 % sweetener had the highest overall liking score of 7.0 ± 1.1, representing moderate liking. The emulsion beverage contained -oryzanol 13.3 ± 0.3 g/mL with the antioxidant activity tested by ABTS of 267.0 ± 37.7 g Trolox equivalent/mL. In conclusion, Nongkhai black jasmine rice bran is a source of bioactive lipids that can be utilized as an ingredient in a plant-based functional drink emulsion

Antioxidant Activity and Alpha-glucosidase Inhibitory Activity of Traditional Herbal Extracts in the Blood and Body Nourishing Group from upper Northern Regions of Thailand

งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษาสารพฤกษเคมีเบื้องต้น ปริมาณฟีนอลิกรวม ฤทธิ์การต้านอนุมูลอิสระ และฤทธิ์การยับยั้งเอนไซม์แอลฟากลูโคซิเดสของสารสกัดสมุนไพรตามภูมิปัญญาท้องถิ่นกลุ่มบำรุงเลือดและบำรุงร่างกายจำนวน 10 ชนิดในเขตภาคตะวันออกเฉียงเหนือตอนบน ได้แก่ แซ่ม้าทะลาย (Erycibe paniculata Roxb) ม่วยเลือด (Gnetum macrostachyum. Hook. f.) สามสิบสองประดง (Bauhinia sirindhorniae K. Larsen & S. S. Larsen) กำลังเลือดม้า (Knema angustifolia Roxb Warb.) รางแดง (Ventilago denticulata Willd.) เอนอ้า (Melastoma malabathricum L.) กำลังเสือโคร่ง (Strychnos axillaris Colebr.) ฝาง (Caesalpinia sappan L.) ช้างน้าว (Ochna integerrima Lour Merr.) และหินระเบิด (Osyris sp.) ผลการทดสอบสารพฤกษเคมีเบื้องต้นจากสารสกัดหยาบเอทานอลของสมุนไพรพบว่า สมุนไพรส่วนใหญ่จะมีสารพฤกษเคมีกลุ่มฟลาโวนอยด์และเทอร์พีนอยด์ และพบกลุ่มอัลคาลอยด์ แอนทราควิโนน คูมาริน ซาโปนิน และแทนนินในสมุนไพรเพียงไม่กี่ชนิด แต่ไม่พบกลุ่มสเตอรอยด์และคาร์ดิแอคไกลโคไซด์ เมื่อนำสารสกัดเอทานอลของลำต้นรางแดง สามสิบสองประดง ฝาง และหินระเบิด มาทดสอบฤทธิ์การต้านอนุมูลอิสระด้วยวิธีดีพีพีเอชพบว่า มีค่าสูงในช่วง 147.03 ± 2.72, 127.30 ± 0.99, 104.94 ± 3.84 และ 73.72 ± 1.46 มิลลิกรัมสมมูลของกรดแอสคอร์บิกต่อกรัมตัวอย่าง ตามลำดับ ซึ่งสอดคล้องกับปริมาณฟีนอลิกรวมซึ่งตรวจพบในปริมาณที่สูงเช่นกัน นอกจากนี้สารสกัดหยาบเอทานอลของสมุนไพรจำนวน 9 ชนิด (ยกเว้นแซ่ม้าทะลาย) ยังแสดงฤทธิ์ยับยั้งเอนไซม์แอลฟากลูโคซิเดสที่ดีกว่าสารมาตรฐานอะคาร์โบส โดยผลการทดลองที่ได้มีค่าแตกต่างอย่างมีนัยสำคัญ (p < 0.05) ดังนั้นสมุนไพรตามภูมิปัญญาท้องถิ่นกลุ่มบำรุงเลือดและบำรุงร่างกายจึงเป็นแหล่งของสารต้านอนุมูลอิสระที่ดี และสามารถพัฒนาเป็นอาหารหรือยาที่สามารถป้องกันโรคเบาหวานได้ต่อไปThis research aims to study phytochemicals, total phenolic content, antioxidant activity and alphaglucosidase inhibitory activity of 10 traditional herbal crude extracts. The medicinal herbs that nourish blood and body from the upper Northeastern of Thailand used in this study included Erycibe paniculata Roxb., Gnetum macrostachyum. Hook. f., Bauhinia sirindhorniae K. Larsen & S. S. Larsen, Knema angustifolia Roxb Warb., Ventilago denticulata Willd., Melastoma malabathricum L., Strychnos axillaris Colebr., Caesalpinia sappan L., Ochna integerrima Lour Merr., and Osyris sp. The results showed that most of the ethanolic herbs extracts contained flavonoids and terpenes. In addition, alkaloids, anthraquinone, coumarin, saponin and tannin were found in some extracts. However, there was no steroids and cardiac glycoside found in the extracts. The extracts of Ventilago denticulata Willd., Bauhinia sirindhorniae K. Larsen & S. S. Larsen, Caesalpinia sappan L., and Osyris sp. showed relatively high antioxidant activity determined by DPPH assay with the value of 147.03 ± 2.72, 127.30 ± 0.99, 104.94 ± 3.84 and 73.72 ±1.46 mg AE/g crude extract, respectively. This is related to the high content of total phenolic compounds in these extracts. Interestingly, all the extracts, except the extract of Erycibe paniculata Roxb., had significantly (p < 0.05) higher alpha-glucosidase inhibitory activity than acarbose. Thus, the traditional blood and body nourishing herbs are good sources of antioxidants and could be further developed to foods or drugs for diabetes prevention

In Vitro Rumen Fermentation of Coconut, Sugar Palm, and Durian Peel Silages, Prepared with Selected Additives

Understanding the nutritive values of fruit peel residues could expand our feed atlas in sustaining livestock production systems. This study aimed to investigate the effects of lactic acid bacteria (LAB), cellulase enzyme, molasses, and their combinations on the fermentation quality and in vitro digestibility of coconut peel (CCP), sugar palm peel (SPP), and durian peel (DRP) silage. The CCP, SPP, and DRP were ensiled in a small-scale silo without additive (control), and with LAB strain TH14 (TH14), molasses, or Acremonium cellulase (AC) using a small-scale silage preparation technique according to a completely randomized design. All fresh peels had sufficient factors for ensiling such as moisture content (78–83%), water-soluble carbohydrates (WSC, 4.20–4.61% dry matter (DM)), and epiphytic LAB population (104–105 colony-forming units (cfu)/g fresh matter (FM)). However, aerobic bacteria counts were high (107–109 cfu/g FM). The fiber content of these fruit peels was high, with lignin abundances ranging from 9.1–21.8% DM and crude protein was low (2.7–5.4% DM). After ensiling, the pH values of the silage were optimal (≤4.25) and lower (p < 0.01) for SPP silage. The addition of molasses+TH14, molasses+AC, and molasses+TH14+AC has the potential to enhance fermentation characteristics and improve chemical composition. Silages treated with molasses alone improved the in vitro digestibility of tropical fruit peels. The residue of tropical fruits has the potential to be used as an alternative feed source for ruminants. Adding molasses, TH14, and AC during silage preparation could improve its nutritive value and digestibility