Effects of state/phase transitions on the quality attributes of mango (Mangifera indica L.) during frozen storage

Effects of different state/phase transitions (temperature fluctuations) on quality attributes of mango cubes during frozen storage were investigated. Temperature of frozen mango was modulated from ?65 °C to different states, namely, rubbery state , partially freeze‐concentrated state () and glassy states ( and ). Results revealed that frozen samples after 4 weeks of storage in a glassy state showed higher quality in hardness, drip loss, colour and ascorbic acid. Quality of mango still continued to change during frozen storage even in the glassy state without temperature fluctuations. Furthermore, there was a significant decrease in quality attributes of frozen mango subjected to temperature fluctuations above and . Current work indicates glassy state storage can improve retention of quality attributes in frozen mango and glassy state without temperature fluctuation was proposed as the most favourable frozen storage condition.     

Powdered barley sprouts: composition,functionality and polyphenol digestibility

This study was performed to evaluate the phytochemical composition, in vitro antioxidant capacity, antihyperglycaemic and anti‐inflammatory activities, and simulated gastrointestinal digestion of 7‐day‐old freeze‐dried barley sprouts (BS), one hybrid and one nonhybrid variety: ‘NS565’ (BSNS) and ‘Golozrni’ (BSG), respectively. BSNS expressed significantly higher (P ≤ 0.05) content of total phenols, chlorophyll and carotenoids. Phenolic compounds were the most dominant bioactives in both BSNS and BSG (713.25 and 479.02 mg GAE 100 g^?1 DW, respectively). BSNS possessed significantly higher (P ≤ 0.05) antioxidant capacity, evaluated by DPPH and ABTS assays, and reducing power ( = 0.54 mg mL^?1; IC₅₀^ABTS = 0.79 mg mL^?1; RP_0.5 = 9.35 mg mL^?1). Antihyperglycaemic and anti‐inflammatory activities of BSNS ( = 1.43 mg mL^?1;  = 1.86 mg mL^?1) were also significantly higher (P ≤ 0.05) than BSG ( = 1.97 mg mL^?1;  = 4.40 mg mL^?1). In vitro simulation of gastrointestinal digestion showed higher release of phenolic compounds in intestinal fluid than in gastric fluid.     

Phenolic profile and changes in the antioxidant activity of crabapple (Malus domestica cv Royalty) fruit during maturation on the tree

The fruits of crabapple (Malus domestica cv Royalty) harvested at six times during fruit maturation on the tree (60, 80, 100, 120, 140 and 160 day after full bloom, DAFB) were evaluated for their antioxidant potentials by various assays such as DPPH, ABTS, superoxide anion, hydroxyl radical and ferric reducing power. Total phenolic and flavonoid were analysed and characterised using HPLC‐DAD‐MS/MS. Results showed that the Royalty fruits harvested on 60 DAFB had the strongest scavenging activity against DPPH, ABTS and radicals ( = 0.37 mg mL^?1,  = 0.19 mg mL^?1 and  = 4906.63 U L^?1) and ferric reducing power (FRAP = 2.85 mol Fe²⁺ per kg dw), which highly correlated with its high amount of total phenolics of 130.17 mg gallic acid equivalents (GAE) per gram dry weight and total flavonoid of 866.15 mg rutin equivalents (RE) per gram dry weight. Eight phenolic compounds were identified in the Royalty extract of 60 DAFB as caffeic acid, eriodictyol rhamnoside, phloretin hexoside I, coumaroyl guinic acid, quercetin hexoside, phloretin hexoside II, quercetin pentoside and quercetin rhamnoside. These findings suggest that Royalty could be potentially used as a promising source of natural antioxidants in the development of functional foods.     

Modelling growth of Lactobacillus plantarum and shelf life of vacuum‐packaged cooked chopped pork at different temperatures

Lactobacillus plantarum growth in a vacuum‐packaged cooked meat product under different storage temperatures (4, 10 and 16 °C) and the relation between the microorganism growth and sensory quality were investigated. The Gompertz model was fitted to experimental counts of L. plantarum showing a good fitting to growth curves at different temperatures. A root‐square secondary model and linear model were satisfactorily fitted to estimated growth rates () and lag times (), respectively. The sensory attributes (colour, flavour, taste, appearance) were also evaluated due to their importance to the global quality (Q). The sensory deterioration was detected several days after L. plantarum reached the stationary phase, that is, 59, 45 and 25 days for 4, 10 and 16 °C, respectively. According to results, sensory deterioration was related to time when microorganism reached late stationary phase, phenomenon known as ‘delayed change’.     

The effect of enzymatic hydrolysis on the biological properties of Oenothera biennis,Borago officinalis and Nigella sativa seedcake by‐products from oil pressing

The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha‐amylase (EC 3.2.1.1) from Aspergillus oryzae, beta‐glucosidase (EC 3.2.1.21) and beta‐glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron‐chelating and radical‐scavenging activity of O. biennis seedcake extract after hydrolysis (IC₅₀ = 0.076 mg mL^?1 and IC₅₀ = 0.050 mg mL^?1) was at a similar level as that nonhydrolyeed (IC₅₀ = 0.070 mg mL^?1 and IC₅₀ = 0.065 mg mL^?1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC₅₀ = 0.095 mg mL^?1) and after enzymatic hydrolysis (IC₅₀ = 0.07 mg mL^?1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.     

The influence of ultrasonic modification on arabinoxylans properties obtained from wheat bran

This work is concerned with modification of wheat bran arabinoxylans by ultrasound irradiation. The average molecular weights of arabinoxylans ranging from 580 000 to 800 000 kDa were yielded by regulating ultrasonic powder (120–480 W) and treat time (15–45 min). The phenolic compounds increased after ultrasound treatment, and arabinose‐to‐xylose ratios ranged between 0.55 and 0.67. FTIR spectroscopy revealed that the major chemical composition of arabinoxylans was unchanged. The maximum storage modulus decreased with the extension of ultrasonic treatment time. The antioxidant capacity test showed that the EC₅₀ values decreased and the values from the ferric reducing antioxidant power decreased after ultrasound treatment. The results suggested that ultrasound is an effective method for the modification of arabinoxylans.     

A Survey of Nitrate and Nitrite Concentrations in Conventional and Organic‐Labeled Raw Vegetables at Retail

A national survey of the nitrate () and nitrite ( ) concentrations in raw and highly consumed vegetables available at retail in the United States was conducted. A total of 194 samples of fresh broccoli, cabbage, celery, lettuce, and spinach categorized as conventional or organic by label were collected from 5 major cities in different geographic regions of the United States and analyzed to determine and concentrations. There were no differences in the mean values of conventional compared with organic vegetables taken from the 5 metropolitan areas. However, significant differences in mean pairwise comparisons between some conventional and organic vegetables for content were observed. The mean concentration of both conventional and organic vegetables ranged between 0.1 and 1.2 mg/kg of fresh weight (FW) with the exception of conventional spinach that contained 8.0 mg/kg FW. Mean contents of conventional broccoli, cabbage, celery, lettuce, and spinach were 394, 418, 1496, 851, and 2797 mg/kg FW, respectively, while their organic‐labeled counterparts averaged 204, 552, 912, 844, and 1318 mg/kg FW. In most cases, organic vegetables were numerically lower in content than their conventional counterparts. Based on survey results, the finding that low levels were observed in some organic vegetables in different cities may warrant further study to determine if true differences exist, due to production practices, seasonal differences, and the magnitudes of those differences. Furthermore, the geographic differences in content of vegetables may flaw estimates of daily and exposure.     

High hydrostatic pressure inactivation kinetics of the endogenous lipoxygenase in crude silver carp (Hypophthalmichthys molitrix) extract

Inactivation kinetics of endogenous lipoxygenase in crude silver carp (Hypophthalmichthys molitrix) extract was studied for thermal (50–80 °C, ambient pressure) and high hydrostatic pressure combined with heat treatment (300–700 MPa at 50–80 °C) process conditions. Lipoxygenase (LOX) inactivation followed first‐order kinetics at all pressure–temperature combinations used. Moreover, LOX inactivation rates became less pressure dependent with increasing pressure at all temperatures studied and also showed less temperature dependence of the enzyme inactivation rate at various high pressure levels tested. It is evident that inactivation kinetics is complex affected by both pressure and temperature. Therefore, response surface methodology (RSM) was attempted to investigate combined temperature–pressure processing conditions on LOX inactivation kinetics in crude silver carp extract samples. In conclusion, the LOX inactivation rate constant was modelled as a function of both temperature and pressure conditions by a quadratic polynomial equation as follows: .     

Impact of wheat bran addition on the temperature‐induced state transitions in dough during bread‐baking process

Wheat bran‐mediated effects on temperature‐induced state transitions of proofed bread dough were studied as function of its level of replacement (5%–15%) to wheat flour. Proofed dough was subjected to rheological tests at small deformations. During heating of proofed dough from 30 °C to 95 °C, the value of elastic modulus (G′) attained its maximum at a temperature () that represented peak gelatinisation temperature (T_P). Dough with 15% bran depicted significant increase in T_P over other formulations. Bran addition increased glass transition temperature (T_g) of dough and suppressed drop in elastic modulus (G′) at T > T_g. The above events resulted in decreased loaf‐specific volume and increased crumb hardness. The former was caused by retarded bubble expansion during initial stages of baking, explained by reduced uniaxial and biaxial extensibilities of dough. Mean bubble size depicted an inverse relationship with the hardness of breadcrumb.     

Determination of certain quality characteristics,thermal and sensory properties of ice creams produced with dried Besni grape (Vitis vinifera L.)

In this study, the effect of adding dried Besni grape (BG) at different concentrations on the physico‐chemical characteristics, colour values, total phenolic and flavonoid contents, glass transition (), melting (), freezing (T_f) and melting (T_m) point temperatures, and sensory properties of ice creams was investigated. Generally, the addition of BG caused a statistically significant (P < 0.01) increase in total solids, ash, fat, viscosity, first dripping times, complete melting times and a* colour values, while it decreased protein, pH, overrun, L*, b*, , , T_f and T_m values. The colour scores of ice cream samples showed a statistically significant increase (P < 0.05) with the increment of BG concentration, while the effects of BG addition on texture, resistance to melting, flavour, gumming structure and overall acceptability scores were not statistically significant.     

A reference isotope dilution headspace GC/MS method for the determination of nitrite and nitrate in meat samples

A novel method for the determination of nitrite and nitrate in meat products is presented. The samples were ground and extracted in hot water with the presence of and internal standards. The solution was buffered with sodium bicarbonate and reacted with triethyloxonium tetrafluoroborate to convert nitrite and nitrate into EtNO₂ and EtONO₂. Such derivatives could be detected by headspace GC/MS in positive chemical ionisation mode with 0.05 µg g⁻¹ and 1.0 µg g⁻¹ LOD. The method was used for and quantitation in the 0.5-300 and 2.5-300 µg g⁻¹ ranges. The method was applied for the analysis of fifteen meat products. Despite minimal sample preparation, the headspace sampling ensured a clean chromatography for over 135 analyses (throughput ten samples per hour). The proposed method offers selective GC/MS detection combined with high-precision isotope dilution calibration, it is suitable for metrological applications and can support regulations on meat safety (European Commission, 2011).     

Effect of the dry ice maceration and oak cask fermentation on colour parameters and sensorial evaluation of Tempranillo wines

The impact of dry ice maceration (DIM) and oak cask fermentation (OCF) on characteristics of Tempranillo wines elaborated in a warm climate has been studied as an alternative procedure to traditional red winemaking (CT) to obtain highly coloured wines. Oenological and colour parameters were measured to determine the influence of these techniques on wines along the winemaking process. DIM and OCF techniques were found significantly different to CT for colour intensity and percentage of blue. Moreover, both induced easily perceptible changes in CIELAB coordinates (lower L*, higher a* and values) than CT and also affect main wine's sensory attributes (e.g. increased polyphenols extraction in DIM and to a lesser extent OCF, and therefore produced wines with higher colour than CT). Although differences tend to decrease with ageing, these practices seem feasible alternatives to improve quality characteristics of young red wines from grapes grown in warm climates.     

Stenocereus griseus (Haw) pitaya as source of natural colourant: technological stability of colour and individual betalains

Stenocereus griseus pitaya has been evaluated as potential natural colourant on the basis of tristimulus colorimetry, differential colorimetry, and individual betalains, not previously conducted in conjunction with this raw material. Different technological treatment conditions were reproduced based on different pHs, temperatures and storage time. According to the results, cold temperatures (4 °C) maintained for longer the initial colour characteristics (L*, and h_ab) of the extracts, whereas h_ab modifications began from the commencement of treatment at room temperature. Highly acidic extracts (pH 4) were the most stable samples in the light of the lower h_ab and changes over time, even at room temperature. Betanin, isobetanin, betanidin and 2-decarboxy-neobetanin were more affected by temperature, whereas the content of the minor betalains significantly (P < 0.05) varied when pH was modified. Moreover, visually appreciable and quantitative colour changes (Δ > 3) were observed among all pH values and temperatures.     

Inactivation efficacy of plasma-activated water: influence of plasma treatment time,exposure time and bacterial species

This study aimed to evaluate the influence of plasma treatment time, bacterial exposure time to PAW and bacterial species on the inactivation efficacy of plasma-activated water (PAW), with additional investigation of the inactivation mechanisms of PAW. Six bacterial species, including Listeria innocua, Staphyloccus aureus, Escherichia coli, Pseudomonas fluorescens, Shewanella putrefaciens and Aeromonas hydrophila were selected as the representative bacteria. The initial bacterial concentration was around 7 log CFU ml⁻¹ after mixing with PAW, and the inactivation efficacy was measured after different exposure times during the 4 °C storage. Scanning electron microscopy (SEM) images of the bacteria after PAW treatment were carried out to inspect the cell structure damage, and physicochemical properties of PAW, including pH, conductivity and long-living reactive species of H₂O₂, , and , were examined. The results showed that the inactivation efficacy of PAW was positively correlated with plasma treatment time and bacterial exposure time, and for the species examined in this study, the Gram-negative species were more sensitive to PAW than the Gram-positive species. Cell structure damage, including shrinkage, distortion, or holes, was observed after PAW treatment. The pH of PAW was acidified to 2.5–2.9, and conductivity was significantly increased to 518.0 μs cm⁻¹. and H₂O₂ were reduced during the 48 h storage, while an increased concentration was observed for . This study demonstrated that the processing parameters of plasma treatment time, exposure time and characteristics of bacteria can significantly affect the inactivation efficacy of PAW.     

Noodle processing,storage time and cooking affect the antioxidant activities and phenolic compounds content of Qingke barley noodles

The impact of noodle processing, storage and cooking on the total phenol content (TPC) and total flavonoid content (TFC) was assessed. Total phenol content (TPC) and total flavonoid content (TFC) of mixed flour were 77.50 and 39.56 mg per 100 g, respectively, and it decreased to 71.80 and 36.30 mg per 100 g after noodle processing. For the fresh Qingke barley noodles (FQBNs), stored at 25 °C, both TPC and TFC decreased significantly during storage. After cooking the fresh noodles, the TPC of the noodles stored for 0 and 4 h increased, while it decreased for the noodles stored for 8, 16 and 24 h; the TFC of all cooked Qingke barley noodles (CQBNs) decreased. Compared with the flour, the DPPH^•, ABTS^•+, HO^• and scavenging ability and ferric reducing antioxidant power (FRAP) decreased significantly (P < 0.05) after noodle processing. For FQBN, increased storage time led to a reduction in antioxidant ability. After cooking, the DPPH^• and HO^• scavenging ability and FRAP of noodles stored at 25 °C for 0 and 4 h, and the ABTS^•+ and scavenging ability of noodles stored at 25 °C for 0, 4 and 8 h increased. Overall, noodle processing, storage and cooking will affect the phenolic compound content and antioxidant activities of barley noodles. Although the shelf life of FQBN is 17 h at 25 °C, from the perspective of nutrition, it is not suitable for long-term storage, and it is best choice to consume it within the first 4 h.     

Challenges in Model Development for Meat Composition Using Multipoint NIR Spectroscopy from At‐Line to In‐Line Monitoring

This study evaluates the efficiency of multipoint near‐infrared spectroscopy (NIRS) to predict the fat and moisture content of minced beef samples both in at‐line and on‐line modes. Additionally, it aims at identifying the obstacles that can be encountered in the path of performing in‐line monitoring. Near‐infrared (NIR) reflectance spectra of minced beef samples were collected using an NIR spectrophotometer, employing a Fabry‐Perot interferometer. Partial least squares regression (PLSR) models based on reference values from proximate analysis yielded calibration coefficients of determination of 0.96 for both fat and moisture. For an independent batch of samples, fat was estimated with a prediction coefficient of determination of 0.87 and 0.82 for the samples in at‐line and on‐line modes, respectively. All the models were found to have good prediction accuracy; however, a higher bias was observed for predictions under on‐line mode. Overall results from this study illustrate that multipoint NIR systems combined with multivariate analysis has potential as a process analytical technology (PAT) tool for monitoring process parameters such as fat and moisture in the meat industry, providing real‐time spectral and spatial information.     

Acid-induced aggregation and gelation of heat-treated chia proteins

This work studied for the first time the acid-induced aggregation and gelation of heat-treated chia protein isolates obtained by extraction at pH 10 or 12 (CPI10 and CPI12, respectively). The aggregation state of proteins was modified during acidification. The size of the aggregates was reduced for both samples when the pH decreased but below pH 4.5 further protein aggregation took place for CPI12. Gelation of CPI12 was completed after about 30 min of acidification with glucone-δ-lactone. By contrast, this period was not enough to reach a constant value in G′ for CPI10. When gelation was ensured, confocal laser scanning micrographs from those gels revealed a coarse and irregular structure with large pores (median size of diameters: 30 μm). Instead, micrographs from CPI12 cold gels showed a more regular and interconnected network, with smaller pores (median size of diameters: 9 μm). These differences are consistent with a higher elastic behaviour ( = 13.6 ± 0.1 Pa).     

Real-time quality authentication of honey using atmospheric pressure chemical ionisation mass spectrometry (APCI-MS)

The aim of this study was to use gas chromatography-mass spectrometry (GC-MS) and APCI-MS techniques to detect adulteration in honey. The key volatile compounds in the headspace of the adulterated honey were marked by GC-MS and their representative fragment ions were utilised in scanning honey samples using the real-time APCI-MS system. The PLS models validated using independent data sets resulted in coefficient of the determination () of 0.97 and 0.96 and root mean square error in prediction (RMSEP) of 2.62 and 2.45 for the GC-MS and APCI-MS data sets respectively. The most efficient volatiles from GC-MS analysis and their corresponding fragment ions m/z from APCI-MS data analysis were then identified and used to develop new PLS models to predict the level of adulteration. The best PLS model gave of 0.95 and RMEP of 2.60% in the independent validation set indicating that the model was very accurate in predicting the level of adulteration.     

A study on kinetics of beer ageing and development of methods for predicting the time to detection of flavour changes in beer

The kinetics of beer ageing were studied based on the development of beer stale flavour with storage time. Results showed that the beer ageing rates at 50 and 60°C were 30.0 and 56 times as fast as those at room temperature, respectively. Based on these findings, two methods (method A and B) for predicting the ‘time to detection of flavour change’ (TDFC) of beer were developed. TDFC is the beer shelf‐life in terms of flavour stability. In method A, beers were stored in a 50°C water bath and the intensity of beer ageing was scored daily. Thus, the range of TDFC of the beer was acquired according to the maximum number of days within which the intensity of beer ageing was ≤2 and the minimum number of days within which the intensity of beer ageing was >2. In method B, the 2‐thiobarbituric acid (TBA) values of a beer were determined before and after 1 day of storage in a 50°C water bath, and the TDFC of the beer was calculated using the equation: where ΔTBA is the increment of TBA value during 1 day of storage at 50°C. Both methods were simple, rapid and accurate. Copyright © 2015 The Institute of Brewing & Distilling     

Adhesion,Cohesion, and Friction Estimated from Combining Cutting and Peeling Test Results for Thin Noodle Sheets

The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional characteristics of 7 types of cooked starch and flour sheets and combine these into a model framework for textural analysis. Cutting tests with wires of diameter 0.30 to 0.89 mm were performed with and without lubrication. Plots of the work done, normalized to the area cut by the wire, showed that this to be linearly related to wire diameter irrespective of lubrication. The oil had little impact on the intercept of these plots, giving cohesive fracture energy (G_c) ranges for these foods between 6.8 and 32.5 J/m². However, lubrication had a strong influence on the slope of the plots. From a comparison of the slopes for lubricated versus unlubricated tests, the kinetic coefficient of friction could be calculated. Values for between 0.007 and 0.521 for different foods were obtained. Peeling tests were performed by lifting sheets vertically away from a fresh mica surface. The adhesive fracture energy G_a, varied from 2.5 to 4.8 J/m². The results can be modeled by plotting the ratio of cohesive to adhesive fracture energy against the coefficient of friction. Thresholds in both axes suggest a physical basis for distinguishing textural perceptions. However, sensory testing with 12 subjects using the 7 food types could not establish whether this framework, however well‐established physically, would apply to oral sensations. A much larger test would be required.