Camellia oil is obtained from the camellia seed with various cultivated species (Camellia. oleifera (C. oleifera), C. meiocarpa, C. vietnamensis, C. yuhsienensis, C. chekiangoleosa, C. semiserrata, ...C. reticulata, C. gigantocarpa, C. octopetala, C. semiserrata var. abliflora etc.), by widely used cold press extraction. As the earliest specie with high oil yield (40–60%) in China, C. oleifera, has become the most commonly available seed for camellia oil manufacturing. Because of its high nutritional and economic value, camellia oil is frequently adulterated with other cheap oils. Additionally, its quality is also susceptible to different species or regions, and various extraction technologies. These factors result in the incorrect labeling of camellia oil, and destabilize the local camellia oil market economies. Therefore, a rapid and accurate method should be prerequisite to authenticate camellia oil.
The officially recommended methods are tedious, and destructive to detect camellia oil adulteration. Therefore, various rapid, precise, and non-destructive techniques should be developed for camellia oil authentication. This present review provides a critical overview of these existing analytical methods in the past few years.
The mass-chromatographic, spectroscopy techniques, and other techniques including electronic noses (e-noses), isotope-ratio mass spectrometry (IRMS), differential scanning calorimetry (DSC), ion mobility spectrometry (IMS) and DNA, have been used for camellia oil authentication. Compared with the traditional chromatographic methods, infrared spectroscopy (IR), Fourier transformed (FT)-Raman, nuclear magnetic resonance (NMR), and fluorescence spectroscopy, combined with chemometrics, respectively, are efficient alternative analytical techniques for camellia oil quality control.
•Camellia oil is frequently adulterated with other cheap oils.•Camellia oil quality is susceptible to different species and extraction methods.•Various rapid and non-destructive techniques could authenticate camellia oil.•Spectroscopy with chemometrics is efficient for camellia oil authentication.
Deep-fried flavor, involving fatty, sweet, burnt, and grilled odors, is an important factor leading to the popularity of deep-fried foods. Comparing with flavors from other conventional and ...innovative thermal treatments, deep-fried flavor is characterized by a rich variety of volatile species (e.g. aldehydes, alcohols, ketones, hydrocarbons, carboxylic acids, furans, pyrazines, and pyridines), intricate formation mechanisms, and a stronger attraction to consumers. By means of comprehensively literature research, this article critically reviews deep-fried flavor deriving from lipid oxidation, Maillard reaction, hydrolysis and amino acid degradation, with a special emphasis to discuss the involvement of lipid oxidation products in the Maillard pathway to form fried volatiles via secondary processes (e.g. fragmentation, rearrangement, and degradation). The reactions are interacted and influenced by various factors, such as frying oils (e.g. fatty acid composition and oil type), food components (e.g. amino acid and sugar), frying conditions (e.g. oxygen concentration, frying time, temperature, pH, and moisture content), and frying types (e.g. vacuum frying and air frying). Overall, well understanding of chemistry origins of deep-fried volatiles is meaningful to economically manipulate the frying process, optimize the fried flavor, and improve the safety and consumer acceptance of deep-fried foods.
•Three stages of flavor development in French fries (FFs): break-in, optimum, and degrading.•Key aroma compounds of FFs and SO were clarified by molecular sensory science.•Oxidation at TPC above ...22.70% in frying oil induced rancid off-flavor.
Flavor is a significant factor determining the popularity of French fries (FFs). The frying process of soybean oil (SO) showed three obvious stages—break-in, optimum, and degrading. Further, in order to distinguish the key aroma compounds in each stage, the FFs prepared in SO with total polar compounds (TPC) of 6.5% (FF7), 16.37% (FF16), and 26.5% (FF27), and their corresponding oils (SO7, SO16, SO27) were chosen for sensory-directed analysis. In the break-in stage (6.50–13.50% of TPC), the flavor of the FFs was light and undesirable due to the lower content of (E,E)-2,4-decadienal. Then at the optimum stage (15.43–22.70% of TPC), the FFs obtained a higher sensory score, mainly owing to the increase of (E,E)-2,4-decadienal with a strong, deep-fried odor. However, in the degrading stage (over 22.70% of TPC), high level of four acids (hexanoic, heptanoic, octanoic, and nonanoic acid), benzeneacetaldehyde and trans-4,5-epoxy-(E)-2-decenal resulted in flavor deterioration in FF27.
This paper aimed to clarify the oil absorption behavior and microstructural changes of fresh and pre-frozen potato strips during frying, and to discuss the effects of freeze pretreatment on the oil ...absorption behavior of potato strips. We investigated the oil distribution; the microstructure changes in the crust, core, and potato strip surface; and the crystal pattern changes in the potato starch during frying by using magnetic resonance imaging, scanning electron microscopy, and X-ray diffraction. We monitored the profile histories of the moisture, oil and potato strip temperature, and oil uptake during frying and cooling. Results showed that during frying, the diversification of oil content in potato and oil infiltration path was closely related to the microstructure, moisture content, and temperature changes of potato strips and the interaction between starch and oil components. Moreover, freeze pretreatment significantly decreased the moisture content (P < .05) and increased oil content (P < .05) of potato strips and affected oil infiltration, microstructural changes, and starch crystallinity (P < .05) during frying. This paper may help in the further understanding of the oil absorption behavior of potato strips during frying and cooling, and may provide ideas for effective oil control measures.
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•Freezing affected oil uptake, microstructure, and the XRD pattern of samples during frying.•The oil absorption behavior of pre-frozen potato strips was investigated.•Starch crystal pattern and crystallinity were affected by freezing and frying.•The oil uptake behavior was related to microstructure changes, heat, and mass transfer.
The flavor formation of fried food experienced an optimum stage, fried food obtained more desirable flavor during this stage. In order to improve the flavor of French Fries (FFs), the optimum stage ...was prolonged by adding several antioxidants (tert-butyl hydroquinone (TBHQ), L-ascorbyl palmitat (L-ap), and rosemary) to the frying soybean oil (SO). The results of sensory evaluation showed that antioxidants had an effect on prolonging the optimum stage. Compared with the control group, the optimum stage of SO added with TBHQ, L-ap and rosemary was prolonged by 25%, 50% and 25%, respectively. Furthermore, antioxidants can effectively inhibit the degradation of some desirable compounds (e. g. (E, E)-2,4-decadienal) and reduce the generation of off-flavor (hexanal, hexanoic acid, heptanoic acid, octanoic acid, and nonanoic acid) during frying. Among them, the TBHQ performed best on inhibiting the increase of total polar compounds, acid value and p-Anisidine value, besides, it had the best effect on reducing the degradation of (E, E)-2,4-decadienal and inhibiting the generation of saturated aldehydes, especially the hexanal. The L-ap showed better abilities to inhibit the generation of off-flavor acids. This study can provide a basis for the effects of different antioxidants in prolonging the optimum stage and inhibiting the off-flavor.
•The antioxidants had an effect in prolonging the optimum stage and improving the flavor of FFs.•TBHQ can inhibit the degradation of (E, E)-2,4-decadienal and the generation of saturated aldehydes.•L-ap performed better in inhibiting the generation of acids with off-flavor.
•Sorghum grain physical characteristics were influenced by genotype.•Polyphenol content and antioxidant activity were affected by sorghum genotype.•Sorghum grain physical characteristics were ...influenced by irrigation treatment.•3-Deoxyanthocyanidin content significantly increased under water deficit regime.•Antioxidant activity of sorghum significantly increased under water deficit regime.
Sorghum grain containing elevated polyphenolic antioxidant content may provide foods with benefits to human health. A study was undertaken to determine the potential role of irrigation on the content of polyphenols and antioxidant levels in sorghum grain. Bound, free and total polyphenols were investigated in six diverse sorghum genotypes grown under either full irrigation or a deficit irrigation regime. Results showed genotype, irrigation and their interaction had a significant effect on polyphenols and antioxidant activity (P⩽0.05). The deficit irrigation treatment significantly increased polyphenol content and antioxidant activity compared to the full irrigation treatment. Of the six genotypes Shawaya black short 1 and IS1311C (brown) showed the highest polyphenols levels and antioxidant activity. Therefore, both irrigation treatments and genotype need to be considered by sorghum breeders and farmers during sorghum production to produce grain with the required levels of polyphenolics and antioxidant activity for targeted end-use.
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•Effects of cultivar and ripeness on Chinese olive oils were studied.•This is the first time to classify Chinese olive oils by flavor characteristics.•The oils from green olive fruits ...may possess better quality and flavor.
The present study was conducted to determine the quality parameters, fatty acid profile, minor compounds (pigments, tocopherols, phenolic compounds, squalene and total sterols) and volatile compounds of olive oils from four common olive cultivars (cv. ‘Koroneiki’, ‘Coratina’, ‘Frantoio’ and ‘Arbequina’) planted in China. The effect of maturation stage on the characteristics of the oils was also evaluated. All samples were classified as extra virgin according to the standards established by IOC. Statistically significant differences (p < 0.05) were observed in the most analytical indicators of the oils among the cultivar and ripening. Coratina oils contained the highest contents of carotenoids, chlorophylls, tocopherols, phenolic compounds and high level of volatiles, demonstrating their excellent nutritional qualities and pleasant flavors. Whereas, Koroneiki oils contained the highest contents of oleic acid and squalene. Further, high levels of total sterols were found in Frantoio and Arbequina oils. Phenolic compounds and volatiles decreased with increase of ripe degree, which indicated the oils from green olive fruits possess better quality and flavor.
•Bullet point 1: CSCE, TP and TBHQ had no significant effect on AV and TGH during deep-fat frying.•Bullet point 2: The CSCE could significantly inhibit the formation of TGD, TGO and ox-TG.•Bullet ...point 3: The content of core aldehydes was significantly reduced by CSCE.•Bullet point 4: CSCE significantly inhabited the formation of monoepoxy oleic acids during frying.
The frying process is an excellent way to obtain food with desirable sensory. However, some harmful substances, such as aldehydes and monoepoxy oleic acids, could also be produced. This study mainly explores the inhibition of polyphenols from the Camellia oleifera seed cake extract (CSCE) on the formation of polar compounds, core aldehydes, and monoepoxy oleic acids during deep-fat frying. The results showed that the CSCE could significantly decrease peroxide, p-anisidine, total polar, and monoepoxy oleic acids compared with other groups. In addition, the CSCE could significantly inhibit the generation of oxidized triacylglycerol polymer (TGP) and oxidized triacylglycerol (ox-TG), indicating its anti-polymerization activity. The total amount of core aldehydes and glycerol ester core aldehydes (9-oxo) in soybean oil was significantly reduced. Furthermore, CSCE had a better inhibitory effect on monoepoxy fatty acids than TBHQ. Our results might be helpful to provide a basis for the search for new natural antioxidants.
•PS with <20% had no significant influence on the sensory results of BT.•The addition of PS had no significant influences on physicochemical properties of BT.•PLM and XRD results showed the ...microstructure of blends were similar to that of BT.•PS could slow the release of capsaicinoid from BT, probably due to high SFC values.
Beef tallow (BT) is the common hotpot oil used in Sichuan hotpot, increasing its characteristic flavors and making it taste better. However, the cholesterol content in BT is high, which may induce cardiovascular diseases. In this study, the effect of palm stearin (PS) on Sichuan hotpot oil was evaluated. The PS: BT blends showed similar physicochemical properties to BT from the results of sensory evaluation, pulsed NMR, DSC, and polar light micrograph (PLM). Furthermore, since spiciness is the essential characteristic of Sichuan hotpot, the digestive properties of capsaicinoids in hotpot oil were used as an evaluation index. The results showed that the digestive properties of capsaicinoids in hotpot oil containing PS were consistent with those without PS. In conclusion, PS can be partially used to replace BT, which can broaden the types of oil used for hotpot and help develop a new hotpot oil.
