During the processing of lemon fruit, a large quantity of seeds is produced as a by-product. These seeds contain valuable components; therefore, required to be evaluated. This study aimed to compare the cold pressed with hexane-extracted lemon seed oils and determine their physicochemical and thermal properties. Cold pressing yielded significantly lower oil (36.84%) than hexane extraction (71.29%). In addition, the concentrations of free fatty acids, peroxides, and -anisidine were lower in the cold pressed oil. Cold pressed oil showed higher total phenolics, α-tocopherol and antioxidant capacity. The major fatty acids found in the cold pressed oil were linoleic and palmitic acids, whereas β-sitosterol and campesterol were the dominant sterols. The crystallization and melting temperatures and enthalpies were also elucidated. In conclusion, this study proved that high quality of lemon seed oils can be produced by the cold pressing technique; this oil can be used in industries such as the food, cosmetic or chemical industries.

The objective of this study was to provide more essential data about the bioactive, aromatic volatile composition and sensory properties of lemon seed oils to possibly establish new application areas of this unexplored new oil. Furthermore, cold pressing and hexane extraction were compared. Catechin, eriocitrin, rutin, naringin, naringenin, hesperidin, neohesperidin and kaempherol as flavonoids, and gallic, syringic, tr-ferulic, rosmaniric and tr-2-hydrocinnamic acids as phenolic acids were quantified in the oils. Naringin, gallic and syringic acids were significantly higher in the cold-pressed sample. Around 30 different aromatic volatiles were identified in both samples, and, for the majority, the concentrations were higher in the coldpressed sample. It was observed that lemon seed oil is very aromatic, mostly characterized by citrus, herbal, terpenic, woody, and floral aroma descriptors. A panel evaluated the oils for sensory properties with 13 different definition terms (clarity, lemon peel, roasted, raw vegetable, grassy, bitter, astringent, waxy, nutty, fatty, spicy and throat-catching). The oil was defined as very bitter, astringent, spicy and throat-catching. In conclusion, lemon seed oil was found unsuitable for direct edible use, but might be preferable for its unique aroma and bioactive components for functional food, pharmaceutical and cosmetic applications.

Sunflower oil-beeswax oleogels at 3% (BWO-3) and 8% (BWO-8) organogelator concentration are prepared to evaluate oleogels as frying medium for potato strip frying against commercial sunflower oil (SO). Rheological and thermal analyses of oleogels prove that the samples are fully solid (20±3°C) and totally liquid (180°C), and thermoreversible. Fresh and used (after frying) fat analyses show that free fatty acidity (FFA), peroxide value (PV) and total polar materials (TPM) are enhanced in all samples at the 7th h, but the relative enhancement levels are lower in oleogel samples. Potato strips fried in oleogels absorb significantly less oil (11.97% and 12.07%) than the control sample (15.20%). Potatoes fried in oleogels are also more bright and yellower than the control sample. Textural profile of the fried potatoes indicates that the samples fried in oleogels are harder, springier, and gummier than that of the control sample. Sensory analysis shows that oleogel fried potatoes get higher sensory scores. Also, overall acceptability of potatoes fried in BWO-8 sample is the highest (8.50) among all. The prepared oleogels are found quite promising frying medium in this study. Further studies with other types of oleogels in extended period frying of various foods are suggested. Practical applications: The development of innovative frying techniques to produce healthier products with lower fat and calorie values are still a remarkable research area. Oleogelation is an emerging strategy used for solid-like oil designing and based on the formation of 3D networks by the addition of organogelators. Oleogelation is accepted as a healthy strategy to structure liquid oils into solid consistency, and oleogels have great edible applications in processed foods, and can be used as a frying medium. This work can guide the use of sunflower oil-beeswax oleogels as a frying medium and allow the development of more healthy fried snacks.

No abstract

The goal of this study is to remove bitterness of cold pressed grapefruit seed oil by adsorbent treatments. The oil is treated with amberlites XAD7, IR120, and IRA400 resins, and natural zeolite, sepiolite, and montmorillonite at 3% (w/w) level. Oil physicochemical properties, oil flavonoid, phenolic acid and phytosterol compositions, oil sensory descriptive analysis, oil consumer preferences as well as properties of the adsorbents are determined. The largest surface area, pore radius, pore volume, and oleic acid adsorption capacity are observed for natural sepiolite, zeolite and XAD7 amberlite. Adsorbent treatment usually reduced oil viscosity, free acidity, and soap content. In removal of flavonoids, natural sepiolite, zeolite and XAD7 resin are the most successful. Reductions from 3.0 to 60.0% are quantified. Phytosterol composition is not changed significantly by adsorbent treatment. Quantitative sensory descriptive data shows that natural sepiolite at first, followed by natural zeolite and amberlite XAD7 reduced bitterness and throatcatching scores almost by half, but consumer preference test results shows that these reductions were not enough for consumers to accept the taste/flavor of the treated oils. Hence, bitterness removal from grapefruit seed oil still remains as a research challenge. Practical Applications: To utilize cold pressed grapefruit seed oil for direct human consumption, the inherent bitterness needs to be removed. This study shows that almost half levels of sensorially perceived bitterness could be removed by natural sepiolite, zeolite, and amberlite XAD7 adsorbents. Although consumers find the treated oils still bitter, the treated oils could be used in formulated food preparations or in blend with other vegetable oils. Cold pressed grapefruit seed oils are treated with various adsorbents to remove bitterness, and then evaluated by analytical techniques and sensory evaluations.