查看更多>>摘要：Cold plasma-induced inactivation of polyphenol oxidase (PPO) in plant-derived foods has been recognized, but the underlying mechanisms are not fully understood. The present study aimed to elucidate the kinetics and mechanisms of PPO inactivation using dielectric barrier discharge (DBD) plasma. The PPO solution (2 mL) was treated with DBD plasma at different times. The results showed that PPO activity decreased by 70.2%, 85.7%, and 94.2% after DBD plasma exposure at 19.4, 26.4, and 32.6 W, respectively, for 3 min. The PPO inactivation curves were well fitted by the Weibull and logistic models. DBD plasma exposure resulted in a significant decrease in the intrinsic fluorescence intensity of PPO, suggesting the disruption of its tertiary structure. Circular dichroism analysis indicated that DBD plasma caused the unfolding of PPO, thereby increasing content of beta-sheets and decreasing the alpha-helices. DBD plasma also induced the oxidative degradation and carbonylation of PPO. After DBD plasma exposure at 26.4 W for 3 min, the surface hydrophobicity of PPO decreased by 60.9%, and the sulfhydryl content declined by 31.2% (p < 0.05). In summary, DBD plasma induced significant changes in the structure and oxidative modification of PPO, which might be responsible for the loss of its enzymatic activity.
查看更多>>摘要：The effect of cultivar on color (CIELab values, anthocyanin content and % polymeric color), chemical composition (vitamin C, total phenolic content) and enzyme activities during thermal processing and subsequent storage (35 degrees C for 14 days) as well as their suitability for puree processing was evaluated for twelve strawberry cultivars. Degradation of anthocyanins, color (based on a* and C* values) and total phenols during thermal processing (95 degrees C, 1 min) was cultivar dependent whereas vitamin C decreased similarly in all cultivars. Despite different levels of POD and PPO activity observed in fresh purees of the different cultivars, these enzymes were completely inactivated in all cultivars after pasteurization. Anthocyanin degradation, which was accompanied by a fade in red color, and loss of vitamin C were remarkable during a 14-day storage period, but the rate differed among the cultivars. In contrast, polymeric color formation was unaffected by the cultivar. Despite the differences in initial chemical composition, Rendezvous, Senga Sengana and 6082 were the cultivars exhibiting the highest anthocyanin stabilities and lowest % polymeric color values after storage, being good candidates for processing, and suggesting that some intrinsic factors (e.g. copigments) in these cultivars could affect anthocyanin stability.
查看更多>>摘要：The combined effects of L-arginine (Arg) and oxidized caffeic acid (OCF) treatment under different salt concentrations on gelling properties of bighead carp (Aristichthys nobilis) surimi gels were investigated. The results showed that the improvement of gel strength and water-holding capacity (WHC) of low-salt (0.5%) surimi gels could be obtained by adding Arg at various levels (0.1-0.4%) rather than OCF (0.1-0.9%, based on protein content). However, the gel strength and WHC of the low-salt surimi gel added with low-dose (0.1%) Arg alone were still far lower than that of regular-salt (3.0%) control. Whereas the significant improvements in low-salt surimi gels could be achieved when 0.1% Arg was combined with various levels of OCF, especially in combination with 0.5% OCF (LC-A-O). The water distribution in LC-A-O was markedly improved and its beta-sheet structure content was significantly increased compared with the low-salt control (P < 0.05). Moreover, a denser and more uniform network structure of LC-A-O was obtained, which was probably due to much stronger and more intra-molecular cross-linking of proteins, via the formation of new adducts between OCF and surimi proteins. Hence, the combined treatment of Arg and OCF showed a potential for improving the gel properties of low-salt surimi.
查看更多>>摘要：The effects of sodium chloride (NaCl) and tert-butylhydroquinone (TBHQ) on 3-monochloropropane-1,2-diol (3MCPD) ester and glycidyl esters (GEs) contents were investigated during long-term deep-frying (177 degrees C, 4 days). The properties of fried food probably affect the formation of 3-MCPD esters and GEs in frying oil. Less NaCl promoted lower 3-MCPD ester and GEs contents, contents of 3-MCPD ester and GEs in the extracted oils from Youtiao (0 mg/kg TBHQ) reduced from 1.272 to 0.360 mg/kg and 0.559 to 0.346 mg/kg, respectively, while the amount of NaCl in Youtiao reduced from 1.5 to 0.0 g/100 g. TBHQ possibly decreased the 3-MCPD ester and GEs contents by suppressing the formation of radical intermediates. The 3-MCPD ester and GEs contents in the extracted oils from Youtiao (1.5 g/100 g NaCl) decreased from 1.221 to 0.893 mg/kg and 0.534 to 0.312 mg/kg, respectively, while the amount of TBHQ in Youtiao increased from 0 to 300 mg/kg. The formation of 3-MCPD esters might be accompanied by decomposition, GEs were rarely generated but decomposed during long-term frying. 3-MCPD esters and GEs entered fried food through frying oil, and the 3-MCPD ester and GEs contents in the extracted oil from Youtiao were closely related to those in the frying oils.
查看更多>>摘要：The objective of the present study was to evaluate the impact of cross-linking treatment of arabinoxylan (AX) on its structure and physiological functions prior to and after the in vitro gastrointestinal digestion. The AX extracted from triticale bran was cross-linked using laccase. The reaction was monitored spectrophotometrically and verified based on the decrease in the ferulic acid content and an increase in the molecular weight. In comparison to the non-cross-linked AX (A-AX), the cross-linked AX (C-AX) exhibited a higher substitution degree, a more compact microstructure, and higher viscosity in the results of FT-IR, SEM, and rheological tests. The hydroxyl radical scavenging ability and the metal ion chelating ability of C-AX were higher than those of A-AX. After passing through the gastrointestinal tract simulated using an in vitro digestion model, in addition to the retentive larger molecular weight and network structure, the antioxidant activity and the glucosidase inhibition activity of C-AX were higher than those of A-AX. In conclusion, the cross-linking treatment of AX increased its tolerance of the extreme environment during the digestive process by modulating its structural characteristics.
查看更多>>摘要：The aim of the study was to determine the effect of microbial transglutaminase enzyme (MTgase) on the volatile compound (VC) profile, free amino acid (FAA) composition, maximum cutting force and aw of pastarma types (sart, kus,go center dot mu, s,ekerpare, kurek, and bohca). In addition, changes in pH, TBARS and instrumental color values during cold storage under MAP (70% N2 + 30% CO2) were examined for 6 months. Transglutaminase caused a decrease in the level of VCs. These treatment had a significant effect on FAA composition. VCs and FAA were affected by pastarma type factor. MTgase increased the maximum cutting force. The effect of transglutaminase on the pH was depends of pastarma types. Four pastarma types (sart, kus,go center dot mu, kurek and bohca) without MTgase showed higher TBARS value than with MTgase. As storage time progressed, L* and a* values decreased depending on pastarma types. In all pastarma types pH ranged between 5.61 and 5.72 during cold storage under MAP condition.
Bustamante, Sandra ZapataGonzalez, Jesus GilSforza, StefanoTedeschi, Tullia...
8页
查看更多>>摘要：Peptides obtained from whey proteins have been associated with different biological properties, but most peptides are usually degraded during the digestive process. In this work, hydrolysates were prepared from a whey protein concentrate obtained by ultrafiltration of Colombian traditional cheese whey and subsequent enzymatic hydrolysis using alcalase, chymotrypsin and flavourzyme. The antioxidant and angiotensin-converting enzyme (ACE) inhibitory properties were evaluated, and peptide profile was determined by ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Changes in the above biological properties and peptide profile after simulated gastrointestinal digestion were then investigated. Before enzymatic hydrolysis, the alcalase hydrolysate showed higher 2,2 '-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity, whereas an inhibition greater than 85% of ACE activity was observed for the alcalase and chymotrypsin hydrolysates. In both tests, the flavourzyme hydrolysates showed lower activities. Different changes in the above biological activities were observed after gastrointestinal digestion of the alcalase and chymotrypsin hydrolysates: ABTS radical scavenging ability increased, whereas ACE inhibitory capacity decreased significantly. The alcalase hydrolysate obtained from ultrafiltrated whey protein concentrate showed high antioxidant and ACE inhibition capacities and higher survivability of peptides after in vitro gastrointestinal digestion.
Colnago, Luiz A.Ferreira, Marcos D.Oldoni, Fernanda C. A.Bernardo, Marcela P....
9页
查看更多>>摘要：Mangoes are usually wasted by consumers due to a physiological disorder known as Internal breakdown (IB). In this study, Palmer mangoes affected by IB were valorized by turning into edible films by continuous solution casting. The films were produced using mango pulps with different IB levels, being 0 (no IB), 2 (1/3-2/3 of IBaffected pulp) and 3 (more than 2/3 of IB-affected pulp), and pectin as a matrix former. The influence of IB level on the physicochemical composition of mango pulps was assessed by pH, soluble solid content, and fiber content analyses. Continuous casting allowed for high productivity of edible films with natural mango color attributes. The films obtained from mango pulps with the highest IB level displayed lowest thickness and water vapor permeability, and largest elongation and opacity, in addition to exhibiting a short composting time (10 days). The physical properties of mango edible films are influenced by the pulp physiochemical composition which changes with IB progression.
查看更多>>摘要：Broccoli is a vegetable consumed globally due to its important nutritional properties, including high concentrations of glucosinolates. Light treatment can be an important tool to delay postharvest senescence. In this work it was evaluated the effect of postharvest continuous white light illumination on glucosinolate metabolism of broccoli heads. Five glucosinolates were identified, one aliphatic (glucoraphanin) and four indolics (glucobrassicin, neoglucobrassicin, 4-methoxyglucobrassicin and 4-hydroxyglucobrassicin). Level of total glucosinolates decreased from 10.1 mu mol/g dry tissue to 1.4 mu mol/g dry tissue in control samples after five days of storage, while the decrement was only until 3.0 mu mol/g dry tissue in treated samples. The expression of genes associated with glucosinolate metabolism decreased during the first three days but this decrease was greater in illuminated samples. After five days, treated samples showed a higher expression (more than twice) in most of these genes with respect to the controls, coinciding with the higher glucosinolate content. Storage of broccoli heads under continuous white light allows to keep higher values of glucosinolate contents while maintaining at the same time the visual quality.
de Melo, Ana Paula Zapelinida Rosa, Cleonice GoncalvesNoronha, Carolina MontanheiroMachado, Michelle Heck...
7页
查看更多>>摘要：In this study, Vitamin D3 (D3) was nanoencapsulated (NP-D3) in zein polymeric matrices to improve its physicochemical stability and availability. An experimental jelly model produced with Acca sellowiana was fortified with NP-D3 to demonstrate its suitability for food fortification. The nanocapsules presented a high encapsulation efficiency of D3 (97.21 +/- 1.87%) with a particle size smaller than 200 nm. The morphological structure showed particles with homogeneous populations, spherical shape, and smooth surfaces. In addition, positive physicochemical stability was obtained under storage, with a low polydispersity index (<0.2) and electrophoretic stability of the zeta potential (24.5 +/- 1.60 mV). DSC demonstrated that NP-D3 is thermally stable, which allows its application in processed foods. The jelly fortified with NP-D3 presented a high content of bioactive compounds (phenolic and flavonoids) with antioxidant capacity. The fortified jelly was microbiologically stable for 90 days, indicating a suitable shelf life. Under the gastrointestinal release simulations, NP-D3 demonstrated an 80% release, with similar behavior when incorporated into the jelly, showing peak release in the duodenum step. Therefore, zein nanoparticles can be a promising approach to prolong the residence time of Vitamin D3 when subjected to food processing and gastrointestinal conditions.
NSTL
Elsevier