Phenolic content and antioxidant activity of young and mature mango (Mangifera indica) and avocado (Persea americana) leave extracts

Polyphenols are groups of secondary metabolites in plants, known with their various biological activities, including their ability to act as antioxidants. Due to the side effects of the use of synthetic antioxidants on human’s health, the search for natural less toxic compounds has significantly increased. This study was carried out to evaluate the phenolic content and antioxidant activity of young and mature avocado (Persea americana) and mango leaves (Mangifera indica). Different extracts were prepared by maceration in methanol, ethanol, cold and hot water. The phenolic content of the extracts was determined using the Folic-Ciocalteu Method. A total of three antioxidant tests were done on the extracts: the 2, 2-diphenyl-1-picrylhydrazyl test (DPPH test), the Ferric reducing antioxidant power and the Hydroxyl radical scavenging activity. Results of these investigations generally showed that the mature leaves of mango and young leaves of avocado exhibited the highest phenolic and flavonoid contents, as well as the antioxidant activity. They can be recommended as good sources of antioxidants to reduce the damages caused by free radicals and reactive oxygenated species in the body. They can also be recommended as a source of antioxidants for the preservation of oils, food containing lipids and pharmaceutical products

Alteration of the lipid of red carp (Cyprinus carpio) during frozen storage

The aim of this study was to determine the oxidative stability of oil extracted from red carp fish frozen up to 9 months at −18°C. To assess oil stability of red carp fish, the analytical indexes and Fourier transform infrared (FTIR) spectroscopy were used. These methodologies used provided similar conclusions. Before frozen storage, the composition of fatty acids showed that red carp oil is a good source of polyunsaturated fatty acids (PUFAs) such as linoleic acid (C18:2ω‐6: 5.29% of total fatty acid), linolenic acid (C18:3ω3: 3.53% of total fatty acid), arachidonic acid (C20:4ω6: 3.68% of total fatty acid), eicosapentaenoic acid (C20:5ω‐3, EPA: 4,06% of total fatty acid), and docosahexaenoic acid (C22:6ω‐3: 3.02% of total fatty acid). During frozen storage, the free fatty acid and peroxide value increased, respectively, from 1.35% to 8.06% in oleic acid and 3.77 to 18.62 meq O2/kg in lipid, while the ratio of PUFA/SFA and polyene index decreased, respectively, from 0.58 to 0.25 and 0.30 to 0.09. The triglycerides also decreased with frozen duration. Therefore, for good fish quality, red carp fish must be stored for <3 months at −18°C

Effect of Different Extraction Methods on the Quality and Stability of Coconut Oil

Aims: This study was conducted in order to assess the effect of different extraction methods on the physicochemical properties of coconut oil. Study Design: Coconut harvesting, cleaning, oil extraction, quality analysis. Place and Duration of Study: General Science Laboratory, School of Agriculture and Natural Resources, Catholic University Institute of Buea, South-West Region, Cameroon, from January 2018 to June 2018. Methodology: Oil samples were extracted from coconuts through five different methods, the traditional method 1 (Boiling and grilling for 2 hours), the traditional method 2 (cooling and grilling for 18 min), the maceration method (Hexane extraction), oven drying + pressing (Pressing 1) and finally sun drying + Pressing (Pressing 2). The obtained oils were then characterised by determining their Peroxide, Thiobarbituric acid, Iodine, Acid values and oxidative stability (Rancimat method). Results: Results showed that the traditional method 1 significantly (p<0.05) alter the quality of coconut oil. The best extraction methods were hexane extraction, pressing methods 1 and 2, as they preserve better the quality of coconut oil and have the highest induction and stability times. Among these, hexane extraction and pressing method 1 were the best. Conclusion: The maceration and pressing methods are the best techniques for coconut oil extraction, as they preserve better its quality

Effect of Roasting on the Proximate Composition, Antioxidant Activity, and Functional Properties of Afrostyrax lepidophyllus (Country Onion) Seeds

Afrostyrax lepidophyllus seed is a nontimber forest product which has a strongly ferocious smell of garlic or onion. It is widely used in central and west Africa in traditional medicine and as spices. The seeds used as spices are generally roasted in order to improve their flavor or aroma. However, roasting conditions vary and also affect the quality of the final product. In order to define the best roasting conditions, A. lepidophyllus seeds were roasted using microwave (200, 300, and 450 W for 10 min), oven (10 and 20 min at 180°C), and pot (5, 10 and 15 min) and blended into flour. The proximate composition, physical, functional, and antioxidant activities of (control) and roasted flours were analyzed. Irrespective of the roasting method, there was a significant increase in fiber content (oven (0.5–1.20%), pot (0.47–1.27%), and microwave (0.50–0.93%)) with increase in time and temperature. The carbohydrate content increased (77.74–81.50%), while protein content dropped with roasting. A significant increase in ash, total phenolic contents (TPC), antioxidant activity (AOA), and functional properties compared to the control was recorded. Roasting A. lepidophyllus seeds in the pot at 250 ± 5°C, 15 min was found to be a good method which maintained or increased its functional and physicochemical properties. With the good TPC and AOA, A. lepidophyllus roasted flour can be a potential ingredient for nutraceutical food development

The effect of soursop‐flower‐enriched fried palm olein on some biochemical and hematological parameters of rats

Abstract This work set out to, first, assess the role of soursop flower extracts (SFE) in limiting palm olein oxidation during the production of plantain chips, before ascertaining the effect of these soursop‐flower‐enriched fried palm olein on some biochemical and hematological parameters of rats. The extracts were added to 1.5 kg of oil at 1000, 1400, and 1800 ppm, while BHT at 200 ppm served as a positive control (PO+BHT), and the oil without additives was the negative control (PO). The samples were subjected to 15 frying cycles. Total oxidation values varied between 5.94 ± 0.0 and 31.58 ± 0.37; 8.08 ± 0.25 and 28.24 ± 0.00 and 13.71 ± 0.24 and 42.71 ± 0.40 respectively for palm olein enriched with SFE, for PO+BHT and for PO. Twenty‐one groups each comprising five rats received, through dietary supplementation, oils subjected to 0, and 5, 10 and 15 frying cycles for a duration of 30 days. The alanine transaminase and aspartate transaminase of rats fed with oils enriched with SFE at fresh states and at 5 frying cycles was comparable to that of the neutral control group (23.45 ± 2.65 and 93.10 ± 3.53 U/L) and lower than that of the negative control group (52.15 ± 2.01 and 124.07 ± 1.89 U/L). The HDL cholesterol of these animals was also comparable to that of the neutral control group (67.82 ± 4.06 mg/dl) and higher than that of the negative control group (50.25 ± 5.20 mg/dl). White blood cells and mean corpuscular volume of rats fed with fried olein previously enriched with SFE were lower than those fed with fried olein without additives. These extracts are recommended as natural antioxidants for the stabilization of palm olein

Optimization of Palm Olein Stability during Storage Using Natural Antioxidants from Cocoa Pods Extract

Aims: The objective of this study is an attempt to optimize palm olein stability during storage using natural antioxidants from Theobroma cacao pods. Study Design: Drying of fresh cocoa pods, extraction of natural antioxidants and its application as antioxidants to optimize oxidative stability of palm olein during storage. Place and Duration of Study: University of Dschang, Cameroon and Council for Scientific and Industrial Research-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, India, from March 2016 to January 2017. Methodology: The plant material was extracted and its reducing power, metal ion chelating activity evaluated. The extract was added in refined palm olein. Peroxide, p-Anisidine and total oxidation (TOTOX) values were determined as response variables to evaluate the effect of storage time and extract concentration during storage of oil. Results: The outcomes showed cocoa pods extract to be efficient in metal ion chelating activity and have the ability to reduce Fe3+ to Fe2+. This extract was also found to be efficient in inhibiting peroxide formation and reducing, in the same way, the amount of secondary oxidation products. At 2000 ppm, Theobroma cacao pods extract has the ability to extend the shelf life (30 months) of palm olein during storage. Conclusion: Theobroma cacao pods can be exploited as an alternative source of synthetic antioxidants for stabilization of palm olein and other oil systems

Comparative Study of the Effect of Piper nigrum (White and Black) and Piper guineense on Lipids Quality of Groundnuts Pudding

This study investigates the effect of white and black Piper nigrum and Piper guineense on lipids quality of oil extracted from groundnuts pudding. This work was carried in the Research Unit of Biochemistry, Medicinal plants, Food Sciences, and Nutrition, Department of Biochemistry, Faculty of Science, University of Dschang, Cameroon, between January 2018 and December 2019. The antioxidant activity of these spices was determined. Cooking by steaming of groundnuts (Arachis hypogaea) pudding was carried out using groundnuts paste with 0 g, 0.5 g, 1 g, 2 g and 4 g of spices and 30 ml of warm water respectively. Oils were extracted from the prepared groundnuts pudding using a mixture of chloroform and methanol. The lipid quality of oil samples was studied by the determination of the peroxide, P-anisidine, total oxidation, thiobarbituric and iodine values. Results revealed that these spices possess non negligible antioxidant properties. Black Piper nigrum (BPN) presented the highest total phenolic (TPC: 85.00 mg GAE/g) and flavonoids (FC: 271.94 mg CE/g) contents. The lowest TPC and FC was observed with the aqueous extract white Piper nigrum (WPN: 52.38 mg GAE/g and 113.32 mg CE/g respectively). The use of these spices in groundnuts pudding preparation contributed to limit the formation of primary and secondary oxidation products of groundnuts pudding oil. It was also observed that white Piper nigrum (WPN) better preserve lipids quality of oils at all concentrations because oil extracted from pudding cooked with 0.5 g, 1 g, 2 g and 4 g presented peroxide values lower than 10 meqO2/kg (2.81 meqO2/kg, 2.99 meqO2/kg, 3.28 meqO2/kg and 5.46 meqO2/kg respectively). In summary these spices especially white Piper nigrum can be used to preserve lipids oxidation during cooking by steaming of groundnuts pudding

Chemical composition and antibacterial activity of oils from Chrysicthys nigrodigitatus and Hepsetus odoe, two freshwater fishes from Yabassi, Cameroon

Abstract Backgrounds Oils of fish origin are a very rich source of Omega − 3 and Omega − 6 fatty acids. They have been suggested to provide numerous health benefits for humans involving antimicrobial properties. Chrysichthys nigrodigitatus and Hepsetus odoe are two fishes well known in Cameroon. The chemical composition and the antibacterial activity of these fishes derived oils are unknown. The study was designed to valorise C. nigrodigitatus and H.s odoe oils activity against food poisoning bacteria. Methods Oils were extracted by pressing and maceration methods. Their quality was assessed by analysing quality indexes including peroxides, acid, iodine, anisidine and thiobarbituric acid values. Chemical analysis was established by gas chromatography coupled to flame ionization detector. Antibacterial activity was evaluated by broth microdilution method. Results C. nigrodigitatus oil obtained by maceration exhibited highest acid (7.33 ± 0.00 mg KOH/g), anisidine (34.5 ± 1.84) and thiobarbituric acid (7.50 ± 0.30 μmol MDA/Kg) values compared to that obtained by pressing method (9.13 ± 0.64 and 6.72 ± 0.34 μmol MDA/Kg) respectively. H. odoe oil obtained by pressing method showed highest peroxide value (6.22 ± 1.31 meq O2/kg). Oil chemical analysis revealed long chain polyunsaturated fatty acids of the ω-3 family: linolenic acid (C18:3); eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) and ω-6 family; arachidonic acid (C20:4). In addition, C. nigrodigitatus oil obtained by pressing and maceration methods showed Minimum Inhibitory Concentrations (MIC) values ranging from 32 to 64 mg/ml. H. odoe oil obtained by pressing method revealed MIC values ranging between 8 and 64 mg/ml. Conclusions C. nigrodigitatus and H. odoe oils have activity against food poisoning bacteria, due to their chemical composition

Oxidative stabilization of RBD palm olein under forced storage conditions by old Cameroonian green tea leaves methanolic extract

Background: Lipid oxidation is responsible for the deterioration of the nutritional and organoleptic qualities of foods. It also leads to the formation in these products of compounds which are harmful for the consumer's health. The synthetic antioxidants used by industries in order to solve this problem are also prone to be toxic and quite volatile at high temperatures. On the other hand, the trend among researchers to replace the synthetic antioxidants with natural ones is increasing because of their potential health benefits. In this study, old Cameroonian green tea leaf methanolic extracts were added in palm olein and its efficiency in delaying the oxidation of oil under forced storage conditions was assessed. Methods: The plant material was extracted with methanol and its total phenolics content evaluated by colorimetry, followed by the qualitative identification of some phenolic antioxidants by HPLC-DAD and ESI-MS. After preliminary antioxidant studies, the extract was added in oil at concentrations that ranged from 200 to 1800 ppm. Oil containing butylated hydroxytoluene (BHT) and oil without antioxidant served as positive and negative controls, respectively. The oxidative stability of these oil samples was evaluated by determining their oxidation induction times on Rancimat (at 110 °C) and measuring their oxidative state by the Schaal oven test method during 30 days of storage at 70 °C. Here, oil samples were collected every 10 days and their peroxide, p-anisidine, total oxidation, thiobarbituric acid, iodine values as well as changes in their linoleic acid profile gas chromatography coupled to flame ionization detector (GC/FID) were evaluated. Results: The outcomes showed the total phenolics content of the extract to be 53.5 mg GAE/g. Gallic acid, epicatechin gallate, gallocatechin and epigallocatechin gallate were the phenolic antioxidants detected. The induction times of palm olein supplemented with the extract (200–1800 ppm) were found to be in the range of 24.8–28.9 h, while those of control and oil containing BHT were 20.1 and 22.7 h, respectively. The extracts, at all concentrations, were also found to be efficient like butylated hydroxytoluene in inhibiting the oxidation of palm olein during 30 days of storage at 70 °C. Conclusion: The investigations showed that old Cameroonian green tea leaves are a viable source of natural antioxidants for delaying palm olein oxidation

Nutritional composition, phytochemical, and functional properties of six soybean varieties cultivated in Cameroon

Abstract The objective of this study was to evaluate the influence of different varieties on the nutritional composition, phytochemical, and functional properties of selected soybean varieties cultivated in Cameroon. Soybean varieties TGX 1835, TGX 2001‐8DM, MAK SOY 1N, MAK SOY 3N, MAK SOY 4N, and SOUNG PUNGUNG 2400 were collected and analyzed for their nutritional composition (proximate composition and mineral content), oil quality (peroxide, thiobarbituric acid, iodine, and acid values), total phenolic content, and functional properties. Results of the proximate composition showed that soybean varieties MAK SOY 3N, MAK SOY 4N, and TGX 1835 had the highest protein and lipid contents. The calcium and potassium contents were expressively higher in soybean variety MAK SOY 4N. Soybean variety MAK SOY 3N portrayed the best magnesium, zinc, and iron contents. The oils from all the six soybean varieties exhibited very good chemical properties as far as their safety is concerned. TGX 1835, MAK SOY 4N, and SOUNG PUNGUNG 2400 had the highest total phenolic content. The functional properties presented by all six soybean varieties were similar. These new varieties can be exploited for their nutritional and technological properties. The population should be encouraged to produce and consume them