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This review critically evaluates and discusses groundwork and recent studies on the extraction, characteristics, properties, bioactivities, and applications of the water-soluble non-starch polysaccharides (WS-NSPs) of root and tuber crops. Early studies have focused on the use of conventional extraction methods for the extraction of the WS-NSPs and there are limited information on the characteristics and properties of the extracted materials. In recent years, novel extraction techniques such as microwave, ultrasound, and enzyme-assisted extractions have been utilized to improve the yield and functionality of the WS-NSPs. However, low yield and co-extraction of other biological compounds remain a challenging obstacle for commercial uses. A better understanding of the characteristics and properties was recently afforded by employing advanced analytical techniques to investigate the chemical composition and molecular structures of the WS-NSPs. Recent bioactivities of the WS-NSPs that demonstrated their potential in the prevention and management of metabolic diseases like diabetes, obesity, cancer, and in improving gut health and immunity had received considerable attention. Also, many studies have confirmed the potential use of the WS-NSPs of root and tuber crops in a wide range of food and pharmaceutical applications. These bioactivities of WS-NSPs warrant further investigations on this interesting biomaterial.

Summary The incorporation of microwave and pulsed electric field (PEF) technologies in optimising the extraction of polyphenols from defatted canola seed cake was determined by Box-Behnken response surface methodology, using three parameters of microwave treatment (power, time and liquid: solid (L:S) ratio) and four parameters of PEF (ethanol concentration, time, frequency and voltage). After microwave and PEF pretreatments, the polyphenols of defatted canola seed cake were extracted by ultrasound treatment under fixed variables (200 W of ultrasonic power, 70 °C of water bath and 20 min of extraction time). The measured responses were total phenolics, total flavonoids, the DPPH˙ scavenging activity and ferric reducing antioxidant power (FRAP). The maximum yields of all responses were achieved under optimum conditions of microwave processing (5 min, L:S ratio of 6.0 and 633.3 W) and PEF-assisted extraction (30 V, 30 Hz, 10% ethanol concentration and 10 s).

Refined hoki oil (RHO) was fractionated to yield polyunsaturated fatty acids (PUFA)-rich fraction and a more solid fraction via dry fractionation (DF) and low-temperature solvent crystallisation (LTSC). Results showed that LTSC yielded a higher percentage (50 %) of the liquid fraction than the DF (30 %) method. The liquid fraction obtained via LTSC (RHO SCL) contains a higher percentage of PUFA (35.2 %) compared to RHO parent oil (28.8 %) and its solid fraction (24.4 %). The melting and crystallisation profiles of the liquid fractions obtained via DSC of LTSC and DF shifted to a lower temperature range than the RHO parent oil and its solid fractions. This may be explained by increased unsaturation in the liquid fractions. Both solid fractions of RHO have similar melting and crystallisation profiles to RHO parent oil. The melting and crystallisation enthalpies and solid fat content of the RHO SCL were lower than RHO parent oil and its solid fraction.

Cold-pressed canola, hemp and flax seed oils were separated into their respective intact triglycerides via high pressure liquid chromatography (HPLC) and their fatty acids analysed. Molecular weights of the triglycerides were determined by electrospray ionization-mass spectroscopy (ESI-MS). Seven triglycerides were collected for flax seed, and trilinolenoyl-glycerol was the most abundant at 25.9%. Seven triglycerides were separated and collected for canola seed oil with dioleoyl-linolenoyl-glycerol as the most abundant (32.5%). Eight triglycerides were separated and collected from hemp seed oil with trilinoleoyl-glycerol as the most abundant (21.9%). The fatty acid profiles of the separated triglycerides for the three oils were determined to confirm the assignments. Hempseed was found to have the highest content of palmitic acid in the triglyceride fractions collected (5.6%); flax and canola had 4.1% and 3.1% respectively. The results of fatty acid composition analysis of the cold pressed oils showed oleic acid to be the most abundant fatty acid in canola oil at 57.56 ± 0.13%. Linoleic acid was the most abundant in hemp seed oil at 55.64 ± 1.21%, and linolenic acid in flax seed oil at 58.84 ± 0.91%. Enzymatic hydrolysis using pancreatic lipase treatment was performed to analyse positional distribution of fatty acids in the oils. Thin layer chromatography (TLC) was used for separation of 2-monoglycerides and free fatty acids. For all three oils, unsaturated fatty acids marginally preferred the sn-2 position on the glycerol backbone. Flaxseed had 59.1% of linolenic acid on sn-2 position. At 58.6%, oleic acid was the most abundant fatty acid at the sn-2 position in canola oil, and for linoleic acid in hemp seed oil, 58.2%. Higher ratios of saturated fatty acids to unsaturated fatty acids were located on sn-1, 3 positions.

The use of microwave and pulsed electric field (PEF) processing to optimize polyphenol extraction from defatted hemp seed cake in mixed solvent of methanol, acetone and water (MAW, 7:7:6 v/v/v) was investigated using the Box-Behnken response surface method. A variables combination for microwave processing of time, microwave power and liquid to solid (L:S) ratio and for PEF (ethanol concentration, time, frequency and voltage) were used in the investigation. Following microwave or PEF treatments, the polyphenols were extracted from the samples under ultrasound with fixed variables (200 W of ultrasonic power, water bath of 70 °C and 20 min of extraction time). The measured responses were total phenolics (TP), total flavonoids (TF), DPPH˙ scavenging activity and ferric reducing/antioxidant power (FRAP). The optimum variables combination for microwave processing (5 min treatment time, L:S ratio of 6, 700 W power and volume 30 mL) and PEF-assisted extraction (voltage (30 V), frequency (30 Hz), ethanol concentration (10 %) and time (10 s)) resulted in maximum yields in all measured responses. The results suggest that microwave processing and PEF can be integrated in processing defatted hemp seed cake to enhance polyphenol extraction and maximize the yield.

Positional distribution of fatty acids in hoki and tuna oils was carried out in the present study via pancreatic lipase hydrolysis and 13Carbon nuclear magnetic resonance (13C NMR) spectroscopy. The two methods gave consistent results for hoki but conflicting values for tuna oil. Saturated fatty acids (SFA) were generally enriched at sn-2 while MUFA were preferentially located at sn-1,3 for hoki by pancreatic lipase treatment. Of the PUFA, DHA in hoki oil was significantly located at sn-2 position, whereas eicosapentaenoic acid (EPA) was randomly distributed via both methods. DHA and EPA in tuna oil were both preferentially located at sn-2 position by NMR spectroscopy. The NMR results for n-3 PUFA were in general agreement with other fish oils studied where DHA showed preference for sn-2 but EPA displayed preferential differences among species. The ratio of DHA in hoki oil at sn-2 position was higher than tuna oil, thus enhancing its bioavailability. The opposite was the case for EPA. For pancreatic lipase hydrolysis of tuna oil, results showed that both DHA and EPA were incompletely recovered along with other PUFA confirming that pancreatic lipase hydrolysis is an unreliable method for positional distribution determination in tuna oil compared to 13C NMR analysis. The ratio of long chain PUFA to triglycerides exceeds 1:1 in tuna oil, causing steric hindrance for hydrolysis of the long chain PUFA residue at sn-1,3 position. Practical applications: Fish oil contains bioactive omega-3 fatty acids (DHA and EPA), however bioavailability and oxidative stability of these omega-3 fatty acids depends on their positional distribution. Pancreatic lipase has been used in determination of positional distribution of fatty acids in fish oil, but this method involves heat and is time consuming and not suitable for fish oil with more than one molecule of PUFA in a single triglyceride. NMR has gained popularity in positional distribution determination of n-3 fatty acids in fish oil as it is a rapid and non-destructive method compared to the conventional chemical and enzymatic methods.

The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p

Enrichment of the omega-3 (n-3) fatty acids of refined hoki oil (RHO) intact triglycerides (TG) and via free fatty acids (FFA), was carried out in the present study using established methods of dry fractionation (DF), low temperature solvent crystallization (LTSC) and urea complexation (UC) and positional distribution of fatty acids in the intact TG was determined by Nuclear Magnetic Resonance (NMR) analysis. Results showed that n-3 fatty acids were enriched in liquid fractions of all methods except DF, where the highest concentration was obtained via the UC method (83.00 %). The FFA form of the oil produced a higher concentration (40.81 %) of n-3 fatty acids via the LTSC method compared to the TG form (31.50 %). The percentages of the total saturated fatty acid (SFA) in the liquid fractions in all methods were lower, ranging from 1.60 % (UC) to 21.44 % (DF) compared to the RHO parent oil (24.05 %). The percentages of total monounsaturated fatty acids (MUFA) in the liquid fractions were similar to the solid fractions except for the UC method where total MUFA was six times higher in the solid fraction. In LTSC-FFA and UC methods, the enrichment factor for EPA was lower, ranging from 1.61 (LTSC-FFA) to 2.83 (UC), than DHA which ranged from 1.64 (LTSC-FFA) to 3.88 (UC). EPA was preferentially located at the sn-1,3 position and DHA was significantly located at the sn-2 position which is the favoured location for intestinal digestion.

(+)-Catechin, the representative catechin in green tea, was incorporated into a full-fat cheese (at 125–500 ppm) followed by ripening for 90 days at 8 °C and digesting for six hours. Determination of pH, proximate composition, total phenolic content (TPC) and antioxidant activity (AA) after manufacture and ripening demonstrated that the addition of (+)-catechin significantly (p ≤ 0.05) decreased the pH of both whey and curd during cheese manufacturing and ripening with no significant (p > 0.05) effect on the moisture, protein and fat contents. (+)-Catechin increased TPC, as well as AA, though the increase was not proportional with increasing the concentration of added (+)-catechin. About 57%–69% of (+)-catechin was retained in the cheese curd, whereas about 19%–39% (depending on the concentration) was recovered from the cheese digesta. Transmission electron micrographs showed that the ripened control cheese had a homogeneous pattern of milk fat globules with regular spacing entrapped in a homogenous structure of casein proteins, whereas the addition of (+)-catechin disrupted this homogenous structure. The apparent interaction between (+)-catechin and cheese fat globules was confirmed by Fourier transform infrared spectroscopy. These associations should be taken into account when incorporating antioxidants, such as (+)-catechin, to create functional dairy products, such as cheese.

Molecular integrations between green tea catechins and milk fat globules in a cheese matrix were investigated using solid-state magic angle spinning nuclear magnetic resonance spectroscopy. Full-fat cheeses were manufactured containing free catechin or free green tea extract (GTE), and liposomal encapsulated catechin or liposomal encapsulated GTE. Molecular mobility of the carbon species in the cheeses was measured by a wide-line separation technique. The (1)H evolution frequency profile of the (13)C peak at 16ppm obtained for the control cheese and cheeses containing encapsulated polyphenols (catechin or GTE) were similar, however, the spectrum was narrower for cheeses containing free polyphenols. Differences in spectral width indicates changes in the molecular mobility of --CH3- or -C-C-PO4- species through hydrophobic and/or cation-π associations between green tea catechins and cheese fat components. However, the similar spectral profile suggests that encapsulation protects cheese fat from interaction with catechins.

Flaxseed oils are used in stir-frying in parts of China. In this study, flaxseed oils were heated at approximately 150 °C as a thin film in a frying pan for 3 and 6 min, respectively. Pan-heating caused loss of tocopherols, plastochromanol-8, phenolic acids and chlorophyll pigments. There was a significant decrease in the linolenic acid resulting in a concomitant relative increase in palmitic, stearic, oleic and linoleic acids in the oils after pan heating. Positive CIELAB “b*” color value, which indicates yellowness and levels of β-carotene and lutein in these oils showed a 42–56% and 8–53% decrease, respectively. Peroxide values, p-anisidine values, percentage of conjugated dienoic acid, specific extinction at 232 and 270 nm and food oil sensor readings of these oils showed significant increases to levels exceeding good oil quality indices. Acid values only showed one to twofold increase from fresh oil values of 0.65–2.23 mg KOH/g of sample. These results indicate that significant levels of oxidation products would be present in flaxseed oils after pan heating. The flaxseed oil with a lower amount of PUFA appeared to be more degraded suggesting that the major factor affecting the oxidative stability of the flaxseed oils during pan-heating was not the degree of unsaturation but was dependent on the complex interaction between the fatty acids and minor constituents in the oils.

Methods to screen the lipid composition of anaerobic food waste digester contents were developed. A colorimetric assay for long-chain fatty acid (LCFA) domains in mixed liquor measuring the partitioning of a lipophilic dye (Sudan III) between the lipid and an aqueous ethanol phase was validated using sheep tallow, deep water fish oil wax esters (orange roughy), olive oil, tripalmitin, tallow mixtures with phosphatidylcholine and cholesterol in a range of 0−10 g/L lipid, and mixed liquor from two different anaerobic digesters. Bacterial and yeast cells at up to 5 g/L did not interfere. The assay correlated well with the gravimetric lipid determination by the standard Bligh and Dyer method. Base-catalyzed esterification was employed as an alternative rapid method to transmethylate esterified fatty acids in the presence of nonesterified lipid for gas chromatographic analysis. Derivatization and solvent extraction of methyl esters was followed by acidification of LCFA soaps and solvent recovery of the liberat...

Anaerobic batch digestion reactors were operated at mesophilic (35°C) and thermophilic (50°C) temperatures with sheep tallow at levels up to 59% of the volatile solids. Tallow was rapidly fermented to long-chain fatty acids (LCFA) and volatile fatty acids (VFA) at 35°C, but was refractory at 50°C. Oleic acid was fermented to palmitic, stearic and acetic acid. Methanogenesis was delayed by characteristic adaptation periods before LCFA and VFA were completely degraded. This demonstrated that wastes with high lipid contents are amenable to stabilization by mesophilic batch digestion.

Summary Physicochemical characterisation and oxidative stability of refined hoki oil, unrefined hoki oil and unrefined tuna oil were carried out in the present study. Tuna oil contains a higher percentage of polyunsaturated fatty acids (42.57%) than the hoki oils (28.79–30.13%), which have higher percentages of monounsaturated fatty acids (45.02–47.16%). All oils showed a good ratio of n-3 to n-6 fatty acid (7.01–8.10). Cholesterol contents in the unrefined hoki (5149.40 μg g−1) and tuna (2045.48 μg g−1) oils were higher than the refined hoki oil (1411.27 μg g−1). Tuna has a higher concentration of natural α-tocopherol (752.49 μg g−1) but lower concentration of vitamin A (110.99 μg g−1) than unrefined hoki oil (151.44 μg g−1 and 997.60 μg g−1, respectively). Higher percentages of unsaponifiable matter were found in the hoki oils (4.90–7.24%) compared with the tuna oil (0.56%). The hoki oils appear more yellow than the tuna oil, which is darker by comparison. Moisture, p-anisidine value and free fatty acid contents in the hoki oils were lower than the tuna oil. Other indicators of oxidative stability showed that the hoki oils were more stable than the tuna oil.

Lipase-catalyzed transesterification of flaxseed oil with cinnamic acid (CA) or ferulic acid (FA) using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate whether the lipophilized products provided enhanced antioxidant activity in the oil. Lipase-catalyzed transesterification of flaxseed oil with CA or FA produced a variety of lipophilized products (identified using ESI-MS-MS) such as monocinnamoyl/feruloyl-diacylglycerol, dicinnamoyl-monoacylglycerol and monocinnamoyl-monoacylglycerol. The free radical scavenging activity of the lipophilized products of lipase-catalyzed transesterification of flaxseed oil with CA or FA toward 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·) were both examined in ethanol and ethyl acetate. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Unesterified FA showed the highest free radical scavenging activity among all substrates tested while CA had negligible activity. The esterification of CA or FA with flaxseed oil resulted in significant increase and decrease in the radical scavenging activity compared with the native phenolic acid, respectively. Based on the ratio of a substrate to DPPH· concentration, lipophilized FA was a much more efficient free radical scavenger compared to lipophilized CA and was able to provide enhanced antioxidant activity in the flaxseed oil. Lipophilized cinnamic acid did not provide enhanced radical scavenging activity in the flaxseed oil as the presence of natural hydrophilic antioxidants in the oil had much greater radical scavenging activity.

Lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate the antioxidant activity of the lipophilized products as model systems for enhanced protection of unsaturated oil. The lipophilized products were identified using ESI-MS. Free radical scavenging activity was determined using the DPPH radical method. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Ferulic acid showed much higher radical scavenging activity than cinnamic acid, which has limited activity. The esterification of cinnamic acid and ferulic acid with triolein resulted in significant increase and decrease in the radical scavenging activity, respectively. These opposite effects were due to the effect of addition of electron-donating alkyl groups on the predominant mechanism of reaction (hydrogen atom transfer or electron transfer) of a species with DPPH. The effect of esterification of cinnamic acid was confirmed using ethyl cinnamate which greatly enhances the radical scavenging activity. Although, compared to the lipophilized cinnamic acid product, the activity was lower. The radical scavenging activity of the main component isolated from lipophilized cinnamic acid product using solid phase extraction, monocinnamoyl dioleoyl glycerol, was as good as the unseparated mixture of lipophilized product. Based on the ratio of a substrate to DPPH concentration, lipophilized ferulic acid was a much more efficient radical scavenger than lipophilized cinnamic acid.