Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.

Pomegranate (Punica granatum L.) seeds are normally waste products from pomegranate fruit processing but they are a valuable source of certain pharmaceutical and nutraceutical compounds. This study was performed to determine and compare the physico‐chemical properties of oils of pomegranate seed extracted by cold pressing from the variety Torshe Malas Iran (TMOI) and two commercial oils from Iran (COI) and Turkey (COT). Fatty acid analysis indicated that all the oil samples had a dominant fatty acid, punicic acid, with the other prominent fatty acids being linoleic and oleic acids. The thermal behavior of the three oils was determined using differential scanning calorimetry, which gave melting points of TMOI (−12.70°C), COI (1.87°C), and COT (2.25°C). TMOI was found to have the most favorable chemical quality attributes, including a low peroxide value (4.67 meq/kg), low free fatty acid content (0.65% as punicic acid), and high total phenolic content (10.44 mg GAE/g sample), followed by COT. Analysis of flavor compounds was conducted using fast gas chromatography‐surface acoustic wave technology, which allowed detection of 13 distinct aromas among the three oils. Overall, the physico‐chemical properties of the three oils were superior to those of pomegranate seed oils extracted using organic solvents reported previously. Practical application: Medical applications of pomegranate seed oil are gaining increasing attention, particularly due to the health benefits of punicic acid. Pomegranate seed oil is also highly suited to specific industrial applications, such as tanning. Despite its importance, little research has been conducted on the physico‐chemical properties of the oil extracted by cold press compared to conventional extraction methods and super critical CO2 extraction. This study shows that superior quality pomegranate seed oil can be extracted simply and without using organic solvents. Extraction of the highly nutritious cold‐pressed oil from pomegranate seeds could enable the generation of substantial revenue for pomegranate processing factories without associated environmental impacts.

Marine lipid contains long-chain n-3 (omega-3) polyunsaturated (PUFA), particularly eicosapentaenoic acid (EPA) (C20:5 n-3) and docosahexaenoic acid (DHA) (C22:6 n-3). Consumptions of these PUFAs have been perceived to be important in human nutrition, health and disease prevention. Tuna, the important industrial fish, discharged substantial amount of wastes. These wastes include the head, liver and intestine. Considerable amount of lipid can be extracted from these wastes. The yield and chemical quality of the oils were determined. All the extracted oils were less than 8%, of which the highest was in head (7.01%). Among different lipid sources (head, intestine and liver), the free fatty acid and peroxide value significantly increased (P < 0.05) from head to liver. The highest iodine value was found in head lipid. The predominant fatty acids in tuna wastes were palmitic (C16:0; 27.63-32.74%), stearic (C18:0; 8.82-13.62%), oleic (C18:1c; 9.16-11.95%) and docosahexaenoic acid (DHA; C22:6; 14.18-15.70%). Differential scanning calorimetery results for tuna waste lipid samples indicated that higher unsaturation in lipid sample showed lower cooling and melting temperature. The n-3 / n-6 ratio of the respective head, liver and intestine lipid samples showed value higher than 1. Due to n-3 fatty acid compound and n-3 / n-6 ratio, lipid from tuna head may be a valuable source for human consumption.