Showing papers in "European Food Research and Technology in 2014"

Comparison on aroma compounds in Chinese soy sauce and strong aroma type liquors by gas chromatography- olfactometry, chemical quantitative and odor activity values analysis

Abstract: In order to elucidate the differences on aroma compounds in Chinese liquors with different aroma styles and the reasons, aroma compounds of Xijiu in soy sauce aroma and strong aroma type were investigated in the research. By gas chromatography–olfactometry (GC–O), aroma compounds in Chinese liquor were chosen for quantitative and odor activity value (OAV) analysis. Ethyl hexanoate, butanoic acid, 3-methylbutanoic acid, hexanoic acid and dimethyl trisulfide were considered to be the most powerful odorants in both liquor samples (aroma intensity ≥3.5) by GC–O. As important aroma compounds (OAV ≥10) in the liquors, ethyl propanoate, ethyl 2-methylpropanoate and 1-propanol were considered with much higher OAVs in soy sauce aroma type liquor, while OAVs of ethyl pentanoate, ethyl hexanoate, ethyl heptanoate, ethyl octanoate, ethyl lactate, hexyl acetate, butyl hexanoate, hexyl hexanoate and hexanoic acid were far lower in strong aroma type liquor. The OAV of ethyl hexanoate in strong aroma type liquor exceeded 50,000, which explained the reason why strong aroma liquor was considered with prominent fruity aroma. The odor differences between the liquors were mainly caused by the manufacturing practices.

Antimicrobial effect and mode of action of chlorogenic acid on Staphylococcus aureus

Abstract: Natural products have been developed as an alternative source of novel antibacterials in combating food-borne pathogens such as Staphylococcus aureus (S. aureus), Salmonella, Listeria monocytogenes. The aims of this study were to investigate the antimicrobial effect of chlorogenic acid (CA) on S. aureus and to elucidate its mechanism of action. Minimum inhibitory concentrations of CA were determined using the agar dilution method. Intracellular pH (pHin), membrane potential, intracellular and extracellular ATP concentrations, and the release of cell constituents were measured to elucidate antibacterial mechanism. Morphological changes induced by CA were examined by electron microscopy. CA induced a decrease in the intracellular ATP concentrations, but no proportional increase in the extracellular ATP. And the release of cell constituents increased significantly when treated with CA. A reduction in pHin and cell membrane hyperpolarization were observed in S. aureus after CA treatment. Electron microscopic observations showed that the cell membrane of S. aureus was damaged by CA. It is concluded that CA inhibited the proliferation of S. aureus and destroyed the permeability of the cell membrane. The findings indicated that CA has the potential to be developed as an alternative to control S. aureus and the diseases associated with this microorganism.

Effects of sweeping frequency ultrasound treatment on enzymatic preparations of ACE-inhibitory peptides from zein

Abstract: In this study, the effect of sweeping frequency ultrasound (SFU) treatment on the degree of hydrolysis of zein and the angiotensin I-converting enzyme (ACE)-inhibitory activity of its hydrolysates were investigated. The mechanism through which ultrasonic pretreatment releases peptides with ACE-inhibitory activity was also studied by fluorescence, circular dichroism (CD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Compared to the control, SFU and fixed frequency ultrasound (FFU) increased the degree of zein hydrolysis by approximately 11.5 %. Sweeping frequency ultrasound pretreatment increased ACE-inhibitory activity of zein hydrolysates by 12.3–116.7 % over the control. At 40 ± 2 kHz, SFU-treated zein hydrolysates had 42.9 % ACE-inhibitory activity, representing an increase of 116.7 % over the control. The fluorescence intensity of SFU- and FFU-treated zein was weaker than in untreated zein, indicating that more Phe, Trp, and Tyr residues were exposed outside the polypeptide chains. CD spectra show that SFU treatment resulted in increase in the α-helix content by 3.4 %, and β-sheet, β-turns, and random coils content by 24.4 %. Analyses of microstructure by SEM and AFM revealed that ultrasonic pretreatment ruptured the fine meshwork structure of zein resulting in the appearance of several micro-holes. We conclude that the SFU pretreatment for 40 ± 2 kHz can remarkably raise the degree of zein hydrolysis and ACE-inhibitory activity of the hydrolysates by altering the second structure of zein and rupturing the smooth surface of protein.

Selection, identification, and application of Aflatoxin B1 aptamer

Abstract: Aflatoxins represent an important class of mycotoxins that are known to be mutagenic, carcinogenic, and teratogenic. Here, we report the use of the systematic evolution of ligands by exponential enrichment technology to screen for a DNA aptamer that recognizes Aflatoxin B1 (AFB1) with high affinity and specificity. AFB1 was first attached to magnetic nanoparticles and then incubated with an ssDNA library. After ten rounds of screening and amplification, 30 aptamer sequences were obtained following enrichment. Combined with a homological and structural analysis and affinity and specificity experiments, aptamer sequence 1, possessing the best affinity and specificity toward AFB1, was finally obtained. The dissociation constants value for aptamer sequence 1 was 11.39 nM. And, the specificity experiment results showed the binding between AFB1 aptamer with five other toxins was very week (did not exceed 15 % compared with AFB1). To demonstrate the potential use of this aptamer for quantitative analysis, a fluorescent bioassay with aptamer 1 was developed. The assay showed a wide linear range, with the AFB1 concentration ranging from 50 to 1,500 ng/L and a detection limit of 35 ng/L. Additionally, the spiked recovery experiment of AFB1 in peanut oil sample exhibited a recovery ratio between 94.2 and 101.2 % which showed good accuracy of the proposed aptamer-based bioassay. This fluorescent method represents a powerful tool for use in the detection of AFB1 without complex sample treatments.

The anti-inflammatory and wound healing properties of honey

Abstract: Honey is a natural product produced by bees and has been used for thousands of years as a medicinal agent and dietary supplement. It is known to cure a wide variety of ailments and can be used as a potent anti-inflammatory and wound healing agent. These vital bioactivities of honey are far less well known than its antibacterial, antioxidant, and any other biological activities. Many clinical trials have been reported and revealed that, when honey is applied to wound, there is a decrease in inflammation and will have a soothing effect. There is much evidence for the anti-inflammatory and wound healing effects of honey in terms of publications in modern medical and scientific journals. The exact mechanism of anti-inflammatory activity and wound healing property of honey has yet to be demonstrated. Possibly there are several mechanisms of action. There are also some reports where honey exerts negligible side effects. The article focuses on the components of honey involved in its anti-inflammatory effect, possible mechanism of action, properties of honey responsible for its wound healing activity, and its adverse effects. Overall the review presents the evidence and explanation for the anti-inflammatory and wound healing properties of honey.

Carotenoid content in vegetative and reproductive parts of commercially grown Moringa oleifera Lam. cultivars from India by LC–APCI–MS

Abstract: Non-availability of standards is the main problem in quantification of carotenoids from plants In this regard, six major carotenoids, ie all-E-luteoxanthin, 13-Z-lutein, all-E-lutein, all-E-zeaxanthin, 15-Z-β-carotene and all-E-β-carotene, were purified using open-column chromatography and thin-layer chromatography Using these purified standards, carotenoids from fresh leaves, flowers and fruits of eight commercially grown cultivars of Moringa oleifera were quantified by liquid chromatography–mass spectrometry All-E-lutein was found as the major carotenoid in leaves and fruits and accounted for 536 and 520 % of the total carotenoids, respectively Among the eight cultivars screened, the cultivar Bhagya (KDM-1) had the maximum amount of all-E-zeaxanthin, all-E-β-carotene and total carotenoids The methodology used in the present investigation for purification and quantification of carotenoids is simplified and hence finds use in screening of carotenoids in other plants Results also explore the M oleifera leaves as a rich source of carotenoids, which is significant for its implications in malnutrition programme to alleviate the vitamin A deficiency

Effect of different halophilic microbial fermentation patterns on the volatile compound profiles and sensory properties of soy sauce moromi

Abstract: The effect of inoculated or co-cultured halophilic lactic bacteria (Tetragenococcus halophilus) and yeasts (Zygosaccharomyces rouxii and Candida versatilis) on the quality of soy sauce moromi was investigated. Results showed no significant change in the major physicochemical properties of soy sauce moromi such as amino nitrogen, total acid, and reducing sugar at the end of fermentation, whereas the composition of free amino acids slightly changed with different fermentation patterns. In the sample inoculated with T. halophilus, the concentration of proline and tryptophan decreased by 18.83 and 50.87 % compared with the blank sample, whereas tyrosine and histidine increased by 32.41 and 27.04 %. In the sample inoculated with Z. rouxii and C. versatilis, the concentration of bitter-tasting lysine, tyrosine, and phenylalanine increased by more than 20 %, and the concentration of tryptophan decreased by 56.71 %. The proportion of amino acids with sweet taste increased by 0.8 % through the co-culture of the three strains. Meanwhile, the total amount of volatile compounds increased by 117.66, 23.28, and 216.88 % in the T. halophilus inoculated sample, two yeast strain inoculated sample, and three strain inoculated sample, respectively. Increased odour activity values of the nine compounds that mainly contributed to the flavour of moromi ranged from 1 to 7.87 times in the three strain inoculated sample. These findings revealed that the co-culture of the three strains during moromi fermentation was beneficial to the improvement of flavour of soy sauce moromi.

Effects of extraction methods on antioxidant activities of polysaccharides from camellia seed cake

Abstract: Four purified polysaccharides (COP-H, COP-U, COP-E, and COP-A) were obtained from seed cake of Camellia oleifera Abel. by hot water extraction, ultrasonic-assisted extraction, enzyme extraction, and alkali extraction, respectively. Their structural characterizations were determined, and antioxidant activities were investigated. The results of FT-IR demonstrated that the characteristic absorption bands exhibited slight difference among four polysaccharides. HLPC analysis presented that the molecular weights were calculated to be 394, 297, 462, and 429 kDa for COP-H, COP-U, COP-E, and COP-A, respectively. GC–MS analysis showed that the monosaccharide compositions were identical to four polysaccharides, while the molecular ratios exhibited significant difference. Four polysaccharides showed antioxidant activities in a concentration-dependent manner. Among four polysaccharides, COP-E showed a higher scavenging activity on DPPH, hydroxyl radical, and superoxide anion radical. These findings suggest camellia seed cake polysaccharides have potential as a natural antioxidant.

Purification and characterization of an alkali-thermostable β-mannanase from Bacillus nealsonii PN-11 and its application in mannooligosaccharides preparation having prebiotic potential

Abstract: An alkali-thermostable β-mannanase from Bacillus nealsonii PN-11 was purified 3896-fold to homogeneity with specific activity of 2,28890 ± 2780 U mg−1 protein and final recovery of 892 ± 009 % The purified β-mannanase was an extracellular monomeric protein with a molecular mass of 50 kDa on SDS–PAGE The first 20 N-terminal amino acid sequence of mannanase enzyme was MVVKKLSSFILILLLVTSAL The optimal temperature and pH for enzyme were 65 °C and 88, respectively It was completely stable at 60 °C for 3 h and retained >50 ± 10 % activity at 70 °C up to 3 h The β-mannanase was highly stable between pH 5–10 and retained >85 % of the initial activity for 3 h The metal ions Ni+2, Co+2, Zn+2 and Mg+2 enhanced the enzyme activity The enzyme remained stable after 3 h of preincubation with most of the tested organic solvents According to substrate specificity study, the purified mannanase had high specificity to locust bean gum which was degraded mainly to mannooligosaccharides (MOS) like mannotriose, mannotetraose and mannopentose These MOS enhanced the growth of Lactobacillus casei but inhibited the growth of Salmonella enterica indicating potential prebiotic properties The properties of the purified β-mannanase from B nealsonii PN-11 make this enzyme attractive for biotechnological applications

Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production

Abstract: The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 °C), time of pretreatment (15–60 min) and pH of egg white solution (7.00–10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 °C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with ≈27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( 30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides <1 kDa (19.04 ± 1.02 %) than ultrasound pretreatment did (11.90 ± 0.53 %), whereas the proportion of peptides <10 kDa were higher in the second case (28.80 ± 0.07 vs. 20.46 ± 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 ± 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes did not significantly improve both antioxidant and functional hydrolysates’ properties.

Polyphenolic contents in Citrus fruit juices: authenticity assessment

Abstract: The contents of 49 polyphenols in sweet orange, tangerine, lemon and grapefruit juices from 18 cultivars grown in Spain were determined by reversed-phase high-performance liquid chromatography with photodiode array detection. Citrus polyphenolic profiles consist of 81–97 % of flavanones, 0.3–13.6 % of flavones, 0.1–6.0 % of flavonols, 0.6–9.6 % of hydroxycinnamic acids and 0.2–0.4 % of coumarins (only found in grapefruit juices). Several markers that allow to distinguish with practical certainty grapefruit and lemon juices between them and from the other Citrus species are reported. Each of these markers is a reliable and useful tool to detect juice adulteration. Grapefruit juice markers were naringenin-7-O-neohesperidoside, naringenin-7-O-neohesperidoside-4′-O-glucose, naringenin-O-hexosylhexoside, hesperetin-7-O-neohesperidoside, naringenin-O-rhamnosylmalonylhexoside, isosakuranetin-7-O-neohesperidoside, hesperetin-7-O-rutinoside, apigenin-6-C-hexoside-O-hexoside, apigenin-7-O-neohesperidoside and scopoletin-O-hexoside. Lemon juice markers were eriodictyol-7-O-rutinoside-4′-O-glucoside, eriodictyol-7-O-rutinoside, diosmetin-6,8-di-C-glucoside, diosmetin-8-C-glucoside, luteolin-7-O-rutinoside, diosmetin-6-C-glucoside and diosmetin-6,8-di-C-hexosideacylhexoside. The markers naringenin-O-hexosylhexoside, apigenin-6-C-hexoside-O-hexoside, scopoletin-O-hexoside, diosmetin-8-C-glucoside and diosmetin-6,8-di-C-hexosideacylhexoside were detected, characterized and quantitatively determined in grapefruit and lemon juices for the first time by our research group, as far as the authors know. Classification models provided by LDA and PLS-DA correctly identify all sweet orange and tangerine juices. Moreover, PLS regression model determines the percentage (10–70 %) of tangerine juice used to adulterate sweet orange juice with a suitable confidence interval (RMSEP = 7 %).

Fermentative aptitude of non-Saccharomyces wine yeast for reduction in the ethanol content in wine

Abstract: Over the last few decades, there has been a progressive increase in the ethanol content in wines due to global climate change and to the new wine styles that are associated with increased grape maturity. This increased ethanol content can have negative consequences on the sensory properties of the wines, human health, and economic aspects. Several microbiological approaches for decreasing the ethanol content have been suggested, such as strategies based on genetically modified yeasts, the adaptive evolution of yeasts, and the use of non-Saccharomyces yeast. In the present study, we investigated the interspecies and intraspecies variability of some non-Saccharomyces wine yeast species under anaerobic fermentation conditions. Across different grape juices and fermentation trials, Hanseniaspora uvarum, Zygosaccharomyces sapae, Zygosaccharomyces bailii, and Zygosaccharomyces bisporus promoted significant reductions in ethanol yield and fermentation efficiency in comparison with Saccharomyces cerevisiae. The diversion of alcoholic fermentation and the abundant formation of secondary compounds might explain the marked reduction in ethanol yield, as determined through the segregation of the majority of the strains according to their species attributes observed using principal component analysis. These data suggest that careful evaluation of interspecies and intraspecies biodiversity can be carried out to select yeast that produces low-ethanol yields.

Nutritional and functional performance of high β-glucan barley flours in breadmaking: mixed breads versus wheat breads

Abstract: The ability of high β-glucan barley (HBGB) flour versus regular commercial barley (CB) to make highly nutritious wheat (WT) blended breads meeting functional and sensory standards has been investigated. Mixed breads obtained by 40 % replacement of WT flour by HBGB flours are more nutritious than those replaced by CB flours and much more than regular WT flour breads in terms of elevated levels of dietary fibre fractions (soluble, insoluble, resistant starch and β-glucans), slowly digestible starch subfraction and bioaccessible polyphenols providing higher antiradical activity. WT/CB and WT/HBGB breads can be, respectively, labelled as source of fibre (3 g DF/100 g food) and high-fibre breads (6 g DF/100 g food), according to Nutritional Claims for dietary fibre foods. The consumption of 100 g of WT/HBGB can meet up to almost 50 % the required dietary fibre, providing a β-glucan intake high enough to meet the requirements of the EFSA health claim (3 g/day), contributing a reduced blood cholesterol level. The techno-functional performance of fresh blended breads and the sensory appreciation were in general preserved or even improved.

Influence of sequential inoculation of Wickerhamomyces anomalus and Saccharomyces cerevisiae in the quality of red wines

Abstract: The use of mixed inoculation of non-Saccharomyces yeasts and S cerevisiae in wine fermentations is of increasing interest for quality enhancement and improved complexity of wines The effect of sequential inoculation of Wickerhamomycesanomalus (formerly Hansenula anomala) with interesting enological properties in terms of secondary metabolite production and a commercial S cerevisiae strain in fermentation of non-sterilized red musts from Mazuela variety has been examined The wines elaborated by sequential inoculation presented higher levels of acetates and ethyl esters, compounds that supply a fruity note, higher levels of lineal alcohols, which are responsible for herbaceous notes and lower concentrations of organic acids, that contribute to increase the aromatic quality, than wines produced by a S cerevisiae monoculture Both types of wines were comparable in levels of volatile acidity, glycerol, lactic acid and succinic acid produced Sensory analysis showed that red wines obtained by mixed fermentations were preferred by 715 % of the tasters and were particularly appreciated for its floral and/or fruity notes

Structuring and texturing gluten-free pasta: egg albumen or whey proteins?

Abstract: The effects of adding egg albumen or whey proteins to pasta made from parboiled rice flour (PR) were investigated. Pasta quality was evaluated in terms of color, furosine content, and cooking properties (water absorption, cooking loss, and consistency at the optimal cooking time). The surface heterogeneity of the cooked and uncooked materials was studied, and some starch properties (pasting properties and starch susceptibility to α-amylase hydrolysis) were assessed, along with the features of the protein network as determined by conditional solubility studies and with ultrastructural features of the cooked products. Egg albumen improved pasta appearance and gave a product with low cooking loss, firmer, and nutritionally more valuable than the other ones. In albumen-enriched pasta, small starch granules appear homogeneously surrounded by a protein network. In the uncooked product, the protein network is stabilized mostly by hydrophobic interactions, but additional disulfide interprotein bonds form upon cooking. Thus, addition of 15 % liquid albumen to PR results in significant improvement of the textural and structural features of rice-based gluten-free pasta.

Impact of sourdough fermented with Lactobacillus plantarum FST 1.7 on baking and sensory properties of gluten-free breads

Abstract: Sourdoughs were produced from buckwheat, oat, quinoa, sorghum, teff and wheat flour using the heterofermentative lactic acid bacteria Lactobacillus plantarum FST 1.7 and added to a basic bread formulation of flour from the same grain type (20 % addition level). Dough rheology, textural (crumb hardness, specific volume) and structural bread characteristics (crumb porosity, cell volume, brightness) of sourdough-containing breads were compared to non-sourdough-containing breads (control). Changes in protein profiles as analysed with capillary electrophoresis were observed in all sourdoughs. Furthermore, sourdough addition led to decreased dough strength resulting in softer dough. No influences on specific volume and hardness on day of baking were found for gluten-free sourdough breads. The staling rate was reduced in buckwheat (from 8 ± 2 to 6 ± 2 N/day) and teff sourdough bread (13 ± 1 to 10 ± 4 N/day), however, not significantly in comparison with the control breads. On the contrary, in wheat sourdough bread, the staling rate was significantly reduced (2 ± 1 N/day) in comparison with control bread (5 ± 1 N/day). Sourdough addition increased the cell volume significantly in sorghum (+61 %), teff (+92 %) and wheat sourdough breads (+78 %). Therefore, crumb porosity was significantly increased in all gluten-free and wheat sourdough breads. Shelf life for sourdough breads was one (teff and oat), two (buckwheat, quinoa and sorghum) and 3 days (wheat) and was not prolonged by sourdough addition. The inferior aroma of breads prepared from the gluten-free flours was also not improved by sourdough addition.

Pressure-induced changes of silver carp (Hypophthalmichthys molitrix) myofibrillar protein structure

Abstract: Silver carp (Hypophthalmichthys molitrix) is one of the major species of freshwater fish in China. Modification of myofibrillar proteins induced by high pressure processing (HPP) has been investigated at pressures ranging from 200 to 500 MPa for 10 min at 20 °C. Influence of high pressure on conformational changes of myofibrils was studied by means of differential scanning calorimetry (DSC), surface hydrophobicity measurement, ultraviolet absorption spectra and second-derivative spectroscopy, intrinsic spectrofluorimetry, Raman spectroscopic analysis and circular dichroism (CD). DSC analyses revealed that the conformational stability of myofibrils is reduced to different extents when they are exposed to a pressure over 200 MPa. More sulfydryl groups as well as hydrophobic regions and amino acid residues which had ultraviolet absorbance had been found significantly after HPP (≥300 MPa). Changes in the Raman spectra were interpreted as the occurrence of secondary structural changes in pressure-induced myofibrillar proteins. CD analysis results demonstrated that α-helix was destroyed after processed at 400 MPa for 10 min. The results implicated that HPP can be used as a possible means of improving the functional properties for growing demand for healthier fish products.

Impact of quinoa bran on gluten-free dough and bread characteristics

Abstract: Besides an appealing texture and taste, gluten-free products should feature a well-balanced nutrient profile, since celiac disease or chronic inflammations are likely to induce malnutrition for involved patients. Due to their composition, pseudocereals represent a promising ingredient to improve nutrient profile of gluten-free bread. The objective of this study was to investigate the impact of quinoa bran on gluten-free bread quality, focusing on volume, pore size and sensory acceptance. The impact of quinoa bran was studied in a gluten-free bread formulation. Five different quinoa bran and two whole grain flour concentrations were evaluated and compared to a control formulation based on rice and corn flour. The rheological properties of quinoa bran as well as the effect on dough development up to a replacement level of 80 % were investigated. Baking tests were carried out, and loaf volume, crumb firmness and sensory characteristics were determined. Quinoa fractions significantly increased carbon dioxide formation (p < 0.05) due to a higher substrate availability. Gas retention was reduced by increasing bran levels (p < 0.05). Oscillation measurements indicated a firming impact of quinoa bran which might have caused a more permeable dough structure, promoting the release of carbon dioxide. With regard to the specific loaf volume significant differences were found across the quinoa milling fractions and the applied levels (p < 0.05). Overall this study demonstrated that 10 % bran improved the bread volume by 7.4 % and enhanced the appearance without compromising the taste.

Changes in the profile of volatile compounds and amino acids during cider fermentation using dessert variety of apples

Abstract: In China, the production of apples is very large even surplus. Developing cider is becoming an important and promising segment of the fruit industry. Fuji apples, a most popular dessert variety in China, were employed to produce cider. Timely monitoring during the fermentation process was conducted by recording the changes in yeast biomass, total sugar content, reducing sugar content, total acidity, yeast assimilable nitrogen, total phenols content, amino acids and volatile compounds. The sugar and nitrogen compounds were consumed smoothly during fermentation. A variety of volatile compounds were detected in the fermentation liquor, mainly including eight higher alcohols, fourteen esters, six fatty acids, three aldehydes, one ketone, one volatile phenol and three terpenes. Their content was changing dynamically throughout the fermentation process. The sensory evaluation revealed a good acceptance of the cider. The results showed that Fuji apples are good raw material for cider and have the potential to be widely used in the China cider industry.

Characterization and density functional theory study of the antioxidant activity of quercetin and its sugar-containing analogues

Abstract: Inhibition of free radicals using quercetin, hyperin and rutin is examined to determine their antioxidant effects and the structure–activity relationships of flavonoids. Two species of the free radicals are used, including hydroxyl radical (·OH) and superoxide anion radical (O2 −·). Density functional theory calculations under the level of B3LYP/6-311G (d) have been utilized to explore the structure, molecular properties and antioxidant abilities of the three flavonoids. Bond dissociation enthalpy (BDE) and frontier molecular orbital energy gap are investigated. They are compared with the experiment results assayed by the spectrophotometric. All of the flavonoids show a high activity on inhibiting ·OH and O2 −· radicals. Scavenging activity determined by half maximal inhibitory concentration (IC50) values of the three flavonoids decreases in the order: quercetin > hyperin > rutin. The calculations show that quercetin owns the lowest BDE values, which agree well with the experimental results of antioxidant activity determined by IC50 values.

Chemical composition and insecticidal activities of the essential oil of Perilla frutescens (L.) Britt. aerial parts against two stored product insects

Abstract: The chemical composition of the essential oil of Perilla frutescens (L.) Britt. aerial parts and its insecticidal activity against Tribolium castaneum and Lasioderma serricorne were investigated. The essential oil of P. frutescens was obtained by hydrodistillation and a total of 34 components in the essential oil were identified with GC–MS. It was found that the main compounds included 2-furyl methyl ketone (71.83 %), decahydro-1-methyl-2-methylene-naphthalene (10.47 %), limonene (5.16 %) and caryophyllene (1.66 %). With a further isolation, the two active constituents were obtained from the essential oil and identified as 2-furyl methyl ketone, limonene. In the progress of assay, it showed that the essential oil and 2-furyl methyl ketone exhibited stronger contact and fumigant activities against the two stored product insects than limonene. Moreover, the essential oil and its constituents exhibited the comparable repellency against the two stored product insects, relative to the positive control, DEET. The results indicate that the essential oil of P. frutescens aerial parts and its isolated compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.

A review of the research progress on the bioactive ingredients and physiological activities of rice bran oil

Abstract: Rice bran oil is not only a nutritious vegetable oil, but also a specialty oil with unique properties and many health benefits. Good stability, appealing flavor and long fry-life enable rice bran oil be used for frying and also to make margarine and shortening and advanced nutritional oils. More importantly, rice bran oil has been reported to have a high potential for making pharmaceuticals and cosmeceuticals. Rice bran oil has surprisingly high levels of nutraceutical components, such as oryzanol, fat-soluble vitamins, sitosterol, other plant sterols and other nutrients. Thus, rice bran oil has been a study focus in relation to its function and application in many countries in the world, as well as a family’s daily health edible oil. This paper summarizes the research progress on the bioactive ingredients and the physiological activities of rice bran oil.

Simultaneous determination of N ε -(carboxymethyl) lysine and N ε -(carboxyethyl) lysine in cereal foods by LC–MS/MS

Abstract: N e-(carboxymethyl) lysine (CML) and N e-(carboxyethyl) lysine (CEL) are two advanced glycation end products. Few studies have focused on the simultaneous determination of CML and CEL content in foods, especially in Eastern foods. In this study, a stable isotope dilution LC–MS/MS method was developed for the simultaneous determination of CML and CEL in foods. The CML and CEL contents in three cereal foods consumed in China were determined by the developed method. Sample preparation consisted of lyophilization, defatting, grinding, reduction, protein precipitation, acid hydrolysis, and solid-phase extraction. The limit of quantification for CML and CEL was 4 and 3 ng/g, respectively. CML and CEL content in fried dough stick was determined for the first time. CML and CEL contents in fried dough sticks were 28.06–66.69 and 10.67–30.22 μg/g of fried dough sticks, respectively. The highest CML and CEL contents in biscuits were 117.53 and 46.09 μg/g of biscuits, respectively. CML and CEL contents in bread crusts were higher than those in bread crumbs.

Effect of plasticizer-type and genipin on the mechanical, optical, and water vapor barrier properties of canola protein isolate-based edible films

Abstract: The mechanical properties, opacity, and water vapor permeability of 5.0 % (w/w) canola protein isolate (CPI) films were investigated in the presence and absence of 1 % (w/w of CPI) genipin, and as a function of plasticizer-type [50 % (w/w of CPI); glycerol, sorbitol, and polyethylene glycol 400]. Findings indicated that tensile strength (TS), puncture strength (PS), and elastic modulus (E) values for CPI films prepared with sorbitol were the highest, followed by PEG-400 and then glycerol, whereas tensile elongation (TE) and puncture deformation (PD) values were greater for films prepared with glycerol, followed by PEG-400 and then sorbitol. In all cases, films prepared with genipin were stronger (greater TS, PS, and E) and less flexible (lower TE and PD) than uncross-linked films. Films also showed greater water vapor permeability when prepared with glycerol, followed by PEG-400 and then sorbitol; however, no differences were observed in the presence and absence of genipin. Opacity was least with glycerol present, followed by sorbitol and PEG-400, and increased in the presence of genipin.

The application of dextran compared to other hydrocolloids as a novel food ingredient to compensate for low protein in biscuit and wholemeal wheat flour

Abstract: Wheat is primarily used for bread-making. However, fungal diseases, grain moisture at harvest and low-protein contents strongly influence the quality of the wheat flour, thus creating challenges for traders, millers and commercial bakers who struggle to produce consistently high-quality products. This paper address the replacement of low-protein/wholemeal flour functionality for bread-making purposes. Three hydrocolloids, xanthan gum, dextran and hydroxypropyl methylcellulose, were incorporated into bread recipes based on high-protein flours, low-protein flours and coarse wholemeal flour. Hydrocolloid levels of 0–5 % (flour basis) were used in bread recipes to test the water absorption. The quality parameters of dough (farinograph, extensograph, rheofermentometre) and bread (specific volume, crumb structure and staling profile) were determined. Results showed that xanthan had negative impact on the dough and bread quality characteristics. HPMC and dextran generally improved dough and bread quality and showed dosage dependence. Volume of low-protein flour breads were significantly improved by incorporation of 0.5 % of the latter two hydrocolloids. However, dextran outperformed HPMC regarding initial bread hardness and staling shelf life regardless the flour applied in the formulation.

Effect of ultrasound treatment on the wet heating Maillard reaction between β-conglycinin and maltodextrin and on the emulsifying properties of conjugates

Abstract: Soy β-conglycinin (7S) was grafted with maltodextrin (MD) by combined ultrasound treatment and wet heating Maillard reaction in this work. The physicochemical and emulsifying properties of 7S–MDH (classical wet heating) and 7S–MDUH (ultrasound-assisted wet heating grafting) have been investigated. Ultrasound treatment could speed up the conjugation process and obtain a protein–polysaccharide conjugate that exhibits superior functionality compared with the one obtained simply by wet heat treatment. The degree of grafting of 32.73 % was obtained in 30 min by ultrasound-assisted wet heating , whereas classical wet heating required 60 min. SDS-PAGE analysis indicated that 7S globulin had become complex with MD to form conjugates of higher molecular weight. Reduction in the contents of lysine and arginine during the graft reaction indicated that these two amino acid residues had the covalent linkage between 7S and MD. The results of secondary structure showed that grafted 7S had decreased α-helix level and increased β-sheet and unordered coil levels. In addition, ultrasound-assisted treatment significantly changes in surface hydrophobicity (H 0), emulsifying activity index and emulsifying stability index of 7S (p < 0.05). Moreover, the emulsions of 7S–MDUH were stable under unfavorable conditions, such as extreme pH, ionic strength and heat treatment temperature, which is mainly due to changes in surface hydrophobicity (H 0) and secondary structure, resulting in a reduction in protein molecular steric hindrance in an increase in molecular flexibility. This study demonstrated that combined ultrasound treatment and wet heating Maillard reaction could potentially be applied as a method to prepare 7S–MD conjugates.

Microencapsulation of capsanthin by self-emulsifying nanoemulsions and stability evaluation

Abstract: The application of natural colorants in food products has been gained more and more attention, not only due to their nutritional advantages, but also their functional properties. The purpose of this research was to encapsulate capsanthin from paprika by nanoemulsions (NEs), and the stability of resultant NEs was evaluated. The NE systems were first optimized by dropwise adding mixed organic phase [5 wt% medium-chain triglyceride (MCT) and 10 wt% surfactant containing span 20 and tween 80 with the weight ratio 1:3 and HLB 13.4] into water phase. Then capsanthin was mixed with MCT as the oil phase. With the presence of capsanthin, the oil phase composition had great impact on the particle size of NEs that the droplet size increased from 30 to 150 nm with increasing capsanthin content. Generally, higher temperature and stirring speed would decrease the particle size, which also depended on the surfactant-to-oil ratio. The stability results demonstrated that there was no obvious change on the capsanthin NE droplet size and entrapped capsanthin content after 1 month storage at ambient temperature. Our results are important for the design of food-grade delivery systems to encapsulate natural lipophilic pigments or ingredients.

The application of d-SPE in the QuEChERS method for the determination of PAHs in food of animal origin with GC–MS detection

Abstract: This paper reports the evaluation of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the determination of polycyclic aromatic hydrocarbons (PAHs) in food of animal origin with GC–MS detection. Although in the available literature, there is a lot of information about sample preparation method for PAHs determination in food samples, but the QuEChERS method application for PAHs determination in food of animal origin has not been reported as yet. The results showed that the best recovery ratios 72.4–110.8 % with relative standard deviation lower than 10 % for all determined compounds were received for the method with ethyl acetate as an extraction solvent, primary–secondary amine and C18 sorbents and evaporation to dryness and dissolving the residues in the hexane. The limit of quantification ranged from 0.0003 to 0.0030 mg kg−1 for pyrene and benzo[a]anthracene, respectively. This method was also used for the determination of PAHs in 15 samples of pork ham. In 8 of 15 samples selected, PAHs were identified. It was observed that in 6 cooked ham and one smoked and cooked samples, any PAHs were found. In other samples, which were smoked and roasted, some low concentration of PAHs was detected. In one sample benzo[a]pyrene (0.0015 mg kg−1), in one sample benzo[b]fluoranthene (0.0015 mg kg−1) and in one sample chrysene (0.0024 mg kg−1) were detected. A number of other less harmful PAHs were also determined. There were no exceedances of maximum levels (according to Commission Regulation (EU) No 835/2011) for determined PAHs in any of the analysed samples.

Characterisation of potential milk coagulants from Calotropis gigantea plant parts and their hydrolytic pattern of bovine casein

Abstract: The steady increase in world cheese demand keeps the search for appropriate coagulating enzymes as rennet substitutes in the scientific focus. This work reports the milk-clotting activities of aqueous crude enzyme (CE) from different parts of Calotropis gigantea using skim milk as substrate. CE from latex exhibited high caseinolytic (86.445 ± 1.055 U/ml) as well as milk-clotting activity (450 U/ml) when compared to other parts. Significant milk clotting index (MCI) was presented by crude enzyme of latex followed by stem, flower and leaf in the decreasing order (p < 0.05). CE from all parts showed an optimum activity at 37 °C, pH 5.5 and 10 mM calcium chloride concentration with excellent pH (4.5–6.5) and thermal stability (30–60 °C). Hydrolysis pattern of casein components by CE during 1 h incubation, as assessed by Tricine–SDS-PAGE, and subsequent peak analysis revealed CE from stem to be closely similar to that of rennin. However, extensive casein hydrolysis was observed when incubated with crude latex enzyme. Casein bands of CE and rennin tended to disappear as incubation progressed to 24 h. Proteolytic degradation was found to be advanced and resulted in complete breakdown of casein fractions unravelling the importance of incubation time as a possible essential requisite for controlled and appropriate casein hydrolysis. The study provides evidence of rennin-like activity associated with C. gigantea plant parts which may serve as a promising source of vegetable milk coagulant.

Towards modelling of fluid flow and food breakage by the teeth in the oral cavity using smoothed particle hydrodynamics (SPH)

Abstract: The mechanical functions of the oral cavity, such as chewing and swallowing, present many modelling challenges. Plastic strain and fracturing occur in food due to interactions with hard and soft tissues, whilst the food moves, collides and mixes with fluid. Smoothed particle hydrodynamics (SPH) is a meshless numerical method that uses particles instead of meshes to discretise material. The Lagrangian nature of SPH means that it is well suited to modelling complexities such as fluid-free surfaces or solid fracture, interactions with complicated deforming boundaries, and temperature and chemical dynamics. We propose a combined SPH–biomechanical model of the oral cavity and present five model applications that address a broad range of material behaviours observed during eating. Interactions between the gums, teeth and the moving tongue with fluids in the anterior oral cavity; biting and chewing of elastoplastic foods; and biting and crushing of brittle foods are each simulated. In each case, the proposed meshless SPH–biomechanical model was found to be well suited to modelling the complex motions, boundary interactions and material responses. The modelling framework shows promise as a tool for simulation of food breakdown and taste release for foods of different material behaviours.