High intensity pulsed electric field as an innovative technique for extraction of bioactive compounds—A review

How to extract bioactive compounds safely and efficiently is one of the problems for the food and pharmaceutical industry. In recent years, several novel extraction techniques have been proposed. To pursue a more efficient method for industrial production, high intensity pulsed electric field (HIPEF) extraction technique has been developed. HIPEF extraction technique, which is based on the conventional pulsed electric field (PEF), provided higher electric field intensity and a special continuous extraction system, and it has confirmed less extraction time, higher extraction yield, and mild processing temperature. So this innovative technique is promising for application of industrial production. This review was devoted to introducing the recent achievement of HIPEF extraction technique, including novel HIPEF continuous extraction system, principles and mechanisms; the critical process factors influencing its performance applications; and comparison of HIPEF extraction with other extraction techniques. In the end, the defects and future trends of HIPEF extraction were also discussed.     

Dietary fiber extraction for human nutrition—A review

Fiber is a mixture of nonstarch polysaccharides that resist digestion by enzymes in the gastrointestinal canal. Some known methods of extracting fiber from plant sources include dry processing, wet processing, chemical, gravimetric, enzymatic, physical, microbial, or a combination of these methods. Modified wet milling is the most cost-effective in the wet milling group, as it uses minimal chemicals, produces high purity products, and uses less water than the other methods. The purity of fibers extracted using the modified wet milling method range from 49.7% to 89.6%. An ideal extraction method should be affordable and produce fibers of high purity.     

Aroma modulation of vegetable oils—A review

Abstract

Aroma is an important quality factor for unrefined vegetable oils especially the condiment oils, whose application and acceptability largely depend on their aroma attributes. The ever-advanced techniques including extraction, separation, detection and identification in flavor science allow hundreds of volatile compounds and aroma-active compounds with high complexity to be identified, which enables us a deep and comprehensive understanding of the aroma in various type of vegetable oils. Studies show that several avenues, mainly including enzymatic reaction, Maillard reaction, Strecker degradation, caramelization, lipid oxidation and thermal degradation of other compounds, account for the formation of these aroma compounds, though some may dominate over others depending on the processing methods/conditions. Based on these findings, novel approaches such as mild-heat treatment, roasting, microwave processing, infrared radiation, enzymatic treatment and fermentation, among others, have been applied to pretreat oil seeds or fruits with the aim to modulate the flavor generation and sensory quality in oils, whereby promising and insightful results are obtained. This review summarizes and discusses the volatile composition and key aroma compounds in common unrefined vegetable oils, their generation pathways as well as the approaches used to modulate their formations.     

Applications and opportunities for ultrasound assisted extraction in the food industry — A review

Ultrasound assisted extraction (UAE) process enhancement for food and allied industries are reported in this review. This includes herbal, oil, protein and bioactives from plant and animal materials (e.g. polyphenolics, anthocyanins, aromatic compounds, polysaccharides and functional compounds) with increased yield of extracted components, increased rate of extraction, achieving reduction in extraction time and higher processing throughput. Ultrasound can enhance existing extraction processes and enable new commercial extraction opportunities and processes. New UAE processing approaches have been proposed, including, (a) the potential for modification of plant cell material to provide improved bioavailability of micro-nutrients while retaining the natural-like quality, (b) simultaneous extraction and encapsulation, (c) quenching of the radical sonochemistry especially in aqueous systems to avoid degradation of bioactives and (d) potential use of the radical sonochemistry to achieve targeted hydroxylation of polyphenolics and carotenoids to increase bioactivity.Industrial relevanceThe application of ultrasonic assisted extraction (UAE) in food processing technology is of interest for enhancing extraction of components from plant and animal materials. This review shows that UAE technology can potentially enhance extraction of components such as polyphenolics, anthocyanins, aromatic compounds, polysaccharides, oils and functional compounds when used as a pre-treatment step in a unit process. The higher yield obtained in these UAE processes are of major interest from an industrial point of view, since the technology is an “add on” step to the existing process with minimum alteration, application in aqueous extraction where organic solvents can be replaced with generally recognised as safe (GRAS) solvents, reduction in solvent usage, and shortening the extraction time. The use of ultrasonic for extraction purposes in high-cost raw materials is an economical alternative to traditional extraction processes, which is an industry demand for a sustainable development.     

Use and abuse of ascorbic acid—A review

The antiscorbutic¹ and ‘extra-antiscorbutic’ functions of ascorbic acid are reviewed. Although megatherapy remains unproven there is substantial evidence that ascorbic acid may affect metabolism in other ways, e.g. by enhancing heavy metal absorption from the alimentary canal. There is little generally accepted evidence that megadoses of ascorbic acid are of themselves toxic.     

Release of Bisphenol A from Polycarbonate—A Review

The release of Bisphenol A (BPA) from polycarbonate baby bottles into food and food simulants is reviewed in the perspective of the current intensive discussions on the risks of this substance. Potential factors that have been reported to influence the release of BPA are reviewed. Unlike most polymers polycarbonate is hydrolyzed under alkaline conditions by scale formation, residual alkaline detergents and boiled water. Data suggest that brushing of the bottle did not raise the release of BPA. Claims that used bottles release more BPA than new bottles and that mineral composition of the aqueous food simulant affect release could not be substantiated. There are indications that aminolysis of polycarbonate by milk and ethanolysis of polycarbonate by 50% ethanol might take place under relevant test conditions.

The relatively few migration data following the test conditions of European food contact material legislation, comply with the specific migration limit. Two test conditions were identified that reflect real use and exposure, and might cause higher release of BPA compared to the test conditions of European food contact material legislation. Further detailed studies are necessary to verify whether these two exposure scenarios are more severe.     

Gelation of gellan – A review

Gellan is an anionic extracellular bacterial polysaccharide discovered in 1978. Acyl groups present in the native polymer are removed by alkaline hydrolysis in normal commercial production, giving the charged tetrasaccharide repeating sequence: → 3)-β-d-Glcp-(1 → 4)-β-d-GlcpA-(1 → 4)-β-d-Glcp-(1 → 4)-α-l-Rhap-(1 →. Deacylated gellan converts on cooling from disordered coils to 3-fold double helices. The coil–helix transition temperature (T_m) is raised by salt in the way expected from polyelectrolyte theory: equivalent molar concentrations of different monovalent cations (Group I and Me₄N⁺) cause the same increase in T_m; there is also no selectivity between different divalent (Group II) cations, but divalent cations cause greater elevation of T_m than monovalent. Cations present as counterions to the charged groups of the polymer have the same effect as those introduced by addition of salt. Increasing polymer concentration raises T_m because of the consequent increase in concentration of the counterions, but the concentration of polymer chains themselves does not affect T_m. Gelation occurs by aggregation of double helices. Aggregation stabilises the helices to temperatures higher than those at which they form on cooling, giving thermal hysteresis between gelation and melting. Melting of aggregated and non-aggregated helices can be seen as separate thermal and rheological processes. Reduction in pH promotes aggregation and gelation by decreasing the negative charge on the polymer and thus decreasing electrostatic repulsion between the helices. Group I cations decrease repulsion by binding to the helices in specific coordination sites around the carboxylate groups of the polymer. Strength of binding increases with increasing ionic size (Li⁺ < Na⁺ < K⁺ < Rb⁺ < Cs⁺); the extent of aggregation and effectiveness in promoting gel formation increase in the same order. Me₄N⁺ cations, which cannot form coordination complexes, act solely by non-specific screening of electrostatic repulsion, and give gels only at very high concentration (above ∼0.6 M). At low concentrations of monovalent cations, ordered gellan behaves like a normal polymer solution; as salt concentration is increased there is then a region where fluid “weak gels” are formed, before the cation concentration becomes sufficient to give true, self-supporting gels. Aggregation and consequent gelation with Group II cations occurs by direct site-binding of the divalent ions between gellan double helices. High concentrations of salt or acid cause excessive aggregation, with consequent reduction in gel strength. Maximum strength with divalent cations comes at about stoichiometric equivalence to the gellan carboxylate groups. Much higher concentrations of monovalent cations are required to attain maximum gel strength. The content of divalent cations in commercial gellan is normally sufficient to give cohesive gels at polymer concentrations down to ∼0.15 wt %. Gellan gels are very brittle, and have excellent flavour release. The networks are dynamic: gellan gels release polymer chains when immersed in water and show substantial recovery from mechanical disruption or expulsion of water by slow compression. High concentrations of sugar (∼70 wt % and above) inhibit aggregation and give sparingly-crosslinked networks which vitrify on cooling. Gellan forms coupled networks with konjac glucomannan and tamarind xyloglucan, phase-separated networks with kappa carrageenan and calcium alginate, interpenetrating networks with agarose and gelling maltodextrin, and complex coacervates with gelatin under acidic conditions. Native gellan carries acetyl and l-glyceryl groups at, respectively, O(6) and O(2) of the 3-linked glucose residue in the tetrasaccharide repeat unit. The presence of these substituents does not change the overall double helix structure, but has profound effects on gelation. l-Glyceryl groups stabilise the double helix by forming additional hydrogen bonds within and between the two strands, giving higher gelation temperatures, but abolish the binding site for metal ions by changing the orientation of the adjacent glucuronate residue and its carboxyl group. The consequent loss of cation-mediated aggregation reduces gel strength and brittleness, and eliminates thermal hysteresis. Aggregation is further inhibited by acetyl groups located on the periphery of the double helix. Gellan with a high content of residual acyl groups is available commercially as “high acyl gellan”. Mixtures of high acyl and deacylated gellan form interpenetrating networks, with no double helices incorporating strands of both types. Gellan has numerous existing and potential practical applications in food, cosmetics, toiletries, pharmaceuticals and microbiology.     

On-line HPLC-ABTS•+ evaluation and HPLC-MS n identification of bioactive compounds in hot pepper peel residues

In this study, bioactive compounds were extracted with aqueous ethanol from hot pepper peel residues, and the crude extract was divided into four fractions with ethyl ether, ethyl acetate and n-butanol in turn. The total phenolics (TP) and total flavonoids (TF) in the extract were analyzed, and the n-butanol fraction contained the highest TP and TF content, which was 13.45 mg gallic acid equivalents/g and 3.39 mg rutin equivalents/g, respectively. The antioxidant activity of the extract was evaluated by radical [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl] scavenging assays. The results of the correlation analysis showed that the antioxidant activity was well correlated with the content of TP and TF (R ² > 0.890). The antioxidant activity of individual antioxidant compound in the extract was evaluated using on-line HPLC-ABTS^?+ assay, and seven antioxidant compounds were identified using HPLC-DAD-MS ⁿ analyses. The main antioxidants identified were naringenin-7-glucoside, procyanidin dimer type B, quercetin-3-O-rhamnoside dimer, kaempferol-3-O-glucoside, kaempferol-3-O-rutinoside, quercetin-3-rutinoside and caffeic acid glycoside dimer. The results showed that hot pepper peel residues contained a certain amount of antioxidant compounds and had a potential application in food products.     

Can sesame consumption improve blood pressure? A systematic review and meta‐analysis of controlled trials

Hypertension is a major risk factor for cardiovascular disease, myocardial infarction, stroke and renal failure. Sesame consumption may benefit blood pressure (BP ) owing to its high polyunsaturated fatty acid, fibre, phytosterol and lignan contents. To clarify this, a systematic review and meta‐analysis of controlled trials was conducted. The PubMed (MEDLINE ), Cumulative Index to Nursing and Allied Health Literature (CINAHL ) and Cochrane Library (Central) databases were systematically searched until August 2016. Eight controlled trials with a total of 843 participants met the eligibility criteria. A random effect meta‐analysis showed that sesame consumption can reduce systolic BP (?7.83 mmHg , 95% CI : ?14.12, ?1.54; P < 0.05, I ² = 99%) and diastolic BP (?5.83 mmHg, 95% CI: ?9.58, ?2.08; P < 0.01, I ² = 98%). To reduce the heterogeneity, the meta‐analysis was limited to high methodology quality trials (n = 4), which resulted in a significant reduction in systolic BP (?3.23 mmHg, 95% CI: ?5.67, ?0.79; I ² = 33%) and a non‐significant reduction in diastolic BP (?2.08 mmHg, 95% CI: ?4.85, 0.69; I ² = 62%). This study concluded that sesame consumption can reduce systolic and diastolic BP. However, further investigations with larger sample sizes and better methodology quality are required to confirm the BP‐lowering effect of sesame consumption. © 2017 Society of Chemical Industry     

Heat transfer phenomena during thermal processing of liquid particulate mixtures—A review

During the past few decades, food industry has explored various novel thermal and non-thermal processing technologies to minimize the associated high-quality loss involved in conventional thermal processing. Among these are the novel agitation systems that permit forced convention in canned particulate fluids to improve heat transfer, reduce process time, and minimize heat damage to processed products. These include traditional rotary agitation systems involving end-over-end, axial, or biaxial rotation of cans and the more recent reciprocating (lateral) agitation. The invention of thermal processing systems with induced container agitation has made heat transfer studies more difficult due to problems in tracking the particle temperatures due to their dynamic motion during processing and complexities resulting from the effects of forced convection currents within the container. This has prompted active research on modeling and characterization of heat transfer phenomena in such systems. This review brings to perspective, the current status on thermal processing of particulate foods, within the constraints of lethality requirements from safety view point, and discusses available techniques of data collection, heat transfer coefficient evaluation, and the critical processing parameters that affect these heat transfer coefficients, especially under agitation processing conditions.     

Bioactive principles from Cordyceps sinensis: A potent food supplement – A review

Cordyceps sinensis (CS) is a well-known entamophagus fungus, naturally distributed in the Tibetan Plateau of Asia and Himalayas. Recently this synonym is transferred to Ophiocordyceps by both scientific and non-scientific communities. It is widely used as a tonic and medicinal food in traditional Chinese medicine (TCM), as it possess wonderful health benefits. To support its functional attributes, various investigations have been carried out to find out its adaptogenic, aphrodisiac, anti-oxidant, anti-aging, neuroprotective, nootropic, immunomodulatory, anti-cancer and hepatoprotective role. Its fruiting portion as well as the larvae possesses potent bio-active fractions and their composition almost found to be similar in both. The bioactive principles are nucleosides, exo-polysaccharides, sterols and, proteins, among others. Among nucleosides, adenosine and cordycepin are the major biochemical markers. Further, different types of solvent extracts and their mixtures exhibit wide range of pharmacological activities, while the water and methanol extracts with the richest sources of nucleosides and polysaccharides also show wide range of pharmacological activities. This review gives a panoramic view of potential health benefits of various classes of bio-active fractions along with the need for sustainable management of CS for human wellness.     

Ginger—Mechanism of action in chemotherapy-induced nausea and vomiting: A review

Despite advances in antiemetic therapy, chemotherapy-induced nausea and vomiting (CINV) still poses a significant burden to patients undergoing chemotherapy. Nausea, in particular, is still highly prevalent in this population. Ginger has been traditionally used as a folk remedy for gastrointestinal complaints and has been suggested as a viable adjuvant treatment for nausea and vomiting in the cancer context. Substantial research has revealed ginger to possess properties that could exert multiple beneficial effects on chemotherapy patients who experience nausea and vomiting. Bioactive compounds within the rhizome of ginger, particularly the gingerol and shogaol class of compounds, interact with several pathways that are directly implicated in CINV in addition to pathways that could play secondary roles by exacerbating symptoms. These properties include 5-HT₃, substance P, and acetylcholine receptor antagonism; antiinflammatory properties; and modulation of cellular redox signaling, vasopressin release, gastrointestinal motility, and gastric emptying rate. This review outlines these proposed mechanisms by discussing the results of clinical, in vitro, and animal studies both within the chemotherapy context and in other relevant fields. The evidence presented in this review indicates that ginger possesses multiple properties that could be beneficial in reducing CINV.