红外辐射联合回火与冷激杀菌技术对胡萝卜粉品质的影响

首先研究不同红外辐射温度(100,110,120℃)及辐射时间(2.5,5,10 min)对胡萝卜粉微生物及品质的影响,然后根据栅栏效应原理研究红外辐射-回火、红外辐射-冷激联合杀菌对胡萝卜粉微生物、色调值、类胡萝卜素含量等品质的影响。结果表明:100℃、10 min的红外辐射处理使细菌和真菌分别降低了1.9 lg(CFU/g)和2.32 lg(CFU/g),110℃、5 min的红外辐射处使细菌和真菌分别降低了1.58 lg(CFU/g)和2.57 lg(CFU/g)。在上述两种处理条件下胡萝卜粉的水分活度从0.238分别降至0.123和0.147,胡萝卜粉中总类胡萝卜素含量从308.8μg/g降至227.8μg/g和238.8μg/g,色差值(ΔE)为9.11和7.89。与红外辐射单独作用相比,联合回火后的处理没有显著影响细菌数目,处理后保持在5.40~5.80 CFU/g,霉菌、酵母数却在处理过程中显著减少,然而减少量较低,总数仍不低于4.5 lg(CFU/g)。红外辐射-冷激联合处理相比红外辐射单独处理,100℃、10 min联合冷激7 d处理可将细菌数量降低0.25 lg(CFU/g),可将霉菌与酵母数量降低0.28 lg(CFU/g),110℃、5 min联合冷激7 d处可将细菌数量降低0.26 lg(CFU/g),可将霉菌、酵母数量降低0.40 lg(CFU/g),且这些处理下胡萝卜粉的色调值、水分活度、类胡萝卜素含量变化不显著。本试验结果表明,红外辐射-冷激处理具有协同效应,且处理过程中胡萝卜粉的色调值及总类胡萝卜素含量不受影响,这为低水分粉体食品红外辐射联合杀菌提供了参考。     

Profiles,antioxidative and ACE inhibitory activity of peptides released from fermented buttermilk before and after simulated gastrointestinal digestion

Bioactive peptides, released from buttermilk by fermentation and/or gastrointestinal proteases, may have health promoting effects. Thus, a comprehensive analysis of the peptide fraction of fermented buttermilk, before and after different phases of simulated gastrointestinal digestion, was performed using ultra high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS). Results showed that digestion simulation substantially changed the peptide profile of fermented buttermilk. A total of 81, 120 and 46 peptides were identified in fermented buttermilk, its gastric and intestinal digests, respectively. These peptides released mostly from β-casein followed by αs1-casein, κ-casein and β-lactoglobulin. In addition, 14 peptides released from milk fat globule membrane proteins (lactadherin, butyrophilin and GlyCAM-1). Bioactivity, mainly angiotensin converting enzyme (ACE) inhibitory activity, has been reported before for only 54 of the detected peptides. Radical scavenging, ferric reducing and ACE inhibitory activities of fermented buttermilk peptides increased significantly after digestion, indicating promotion in fermented buttermilk-peptide bioactivity by gastrointestinal digestion.     

Garden cress oil as a vegan source of PUFA: Achieving through optimized supercritical carbon dioxide extraction

With more people shifting to healthier and environment-friendly lifestyles, the vegan diet has recently gained popularity. Nevertheless, this kind of diet comes with its own limitations in terms of adequate availability of nutrients, for example, essential fatty acids. The primary source for these includes fish and other marine animals, hence not accepted by the vegan population. The plant source is limited. The present work focuses on exploring garden cress (GC) seed oil - an easily available seed, with considerable polyunsaturated fatty acids (PUFA). Conventionally, Soxhlet extraction of vegetable oils is done using solvents like hexane. However, selective extraction of PUFA, phytosterols, and tocopherols could be done by supercritical-CO₂ (SC-CO₂) extraction of oil from the GC seeds with proper optimization of extraction parameters. The PUFA content was found to be 38% in the case of oil extracted with n-hexane. This was enriched to nearly 50% PUFA, when extracted at 350 bar pressure, 60 °C temperature, and 30 g/min flow rate in case of SC-CO₂ extraction. At similar conditions, even tocopherol contents were improved significantly from 486 to 1138 ppm. Further, oil enriched with unsaponifiable matter (2.3%) containing major phytosterols like campesterol, stigmasterol, β-sitosterol, and isofucosterol was obtained at 20 g/min flow rate itself. Another major advantage of SC-CO₂ extraction is the selective extraction of oil from the seed, leaving behind the phospholipids. This in turn eliminates one step of refining, thereby making the process economically viable. The use of co-solvents resulted in nutritionally enriched GC seed oil at a pressure of 250 bar. It is quite evident from the findings of this study that, careful selection of process parameters of SC-CO₂ extraction of GC seed oil can result in a nutritionally enriched vegan source of PUFA, using an emerging cleaner and greener technology.Industrial relevanceThere is a huge demand for newer vegan sources of PUFA. GC seed oil can be one of them. This investigation aimed at process development for extracting PUFA and tocopherol, phytosterol enriched GC oil using eco-friendly SC-CO₂ extraction. SC-CO₂ extraction is becoming more popular and the economic feasibility is proven for the higher scale of operation. As this oil can be encapsulated and sold at a reasonably good price, this work has significant industrial relevance.     

Insights from proteome to phosphorylated proteome: deciphering different regulatory mechanisms in goat muscles with high- and low-meat quality

To investigate the inner mechanisms of meat quality differences between high-quality (HQ) and low-quality (LQ), a comparative quantitative study between longissimus thoracis and external intercostals of goat muscle was performed from proteome to phosphorylated proteome using RP-HPLC in combination with the ‘isobaric tag’ for relative and absolute quantitation (iTRAQ) labelling strategy. Altogether, 1441 proteins were identified in our study, of which 673 were phosphoproteins, and a total of twenty were common differentially expressed proteins. Myosin, carbonic anhydrase, and phosphoglucomutase could be used as proteins marker for HQ and LQ meat. Bioinformatics analysis showed that these proteins exhibited different rates for glycolysis and oxidative phosphorylation reaction, thus causing the different pH and NADH change rates, and resulting in better colour, tenderness, and water retention in HQ meat. The release of Ca²⁺ and adenosine triphosphate changed the meat quality through calcium signalling. Our finding provides a comprehensive view of proteome changes and their phosphorylation levels in goat muscle, involved in producing meats of different muscle parts. It also gives a better understanding of the regulation of protein on various biological processes that determine the final meat quality attributes.     

Mobility and distribution of eight fungicides in surface,skin and pulp in grapes. An application to pyraclostrobin and boscalid

The study discusses the mobility and distribution of vinclozolin, dichlofluanid, penconazol, captan, quinoxyfen, fluquinconazol, boscalid and pyraclostrobin residues in surface, skin and pulp in red grapes. A lab test was carried out by immersing grapes in solutions with different concentrations of fungicides and for different periods of time; followed by a determination of the fungicide residues by GC-ECD with an additional confirmation by GC-MS. The distribution between surface, skin and pulp of the grapes was also determined. The percentage sorption ranged from 6.4 to 116%. Results showed that sorption values depended on the time that grapes had been in contact with the fungicide solutions, but not on the initial concentration of solutions. Residues were mainly found in skin, with percentages ranging from 53.0 to 88.4% of total residues. In pulp, these values ranged from 9.6 to 41.7%. Pyraclostrobin showed higher penetration than the other compounds.A field test using three new commercial formulations containing pyraclostrobin, boscalid and a mixture of both, was carried out by applying these formulations to a vineyard. When fungicides were applied individually the ratios of the skin/pulp residues were similar to those obtained in lab; whereas when a mixture of both pesticides was sprayed results showed a lower penetration of the fungicides in the grape pulp.     

Staling of potato and wheat steamed breads: physicochemical characterisation and molecular mobility

To clarify the physicochemical characterisation and water status of potato steamed bread (PSB) and wheat steamed bread (WSB) during the staling process, texture, amylopectin retrogradation, crystalline structure, water migration and microstructure were evaluated by texture analysis, differential scanning calorimetry, X-ray diffraction, nuclear magnetic resonance (¹H NMR) and scanning electron microscopy (SEM). Results showed that starch molecules in PSB and WSB were recrystallised and formed B-type starch, which had a positive correlation with hardness and thermal enthalpy. Compared to WSB, PSB had a relatively low B-type crystallinity; moreover, a smaller decrease of free water in PSB was also detected in the NMR test, which indicated that more moisture can be used to plasticise crumb, thus contributing to a softer texture of PSB. SEM revealed that the amount and size of the cracks on the interface of starch and gluten matrix in WSB increased with the prolongation of storage time.     

Effects of ultrasound-assisted enzymatic hydrolysis and monosaccharides on structural,antioxidant and flavour characteristics of Maillard reaction products from sweet potato protein hydrolysates

Effects of ultrasound (US)-assisted enzymatic hydrolysis and different monosaccharides (arabinose; xylose, XY; galactose and glucose) on peptide structure, antioxidant activities and flavour characteristics of Maillard reaction products (MRP) from sweet potato protein hydrolysates were investigated. US markedly enhanced the MR progress, and USXY showed the lowest pH value of 5.04, the highest browning intensity and fluorescence intensity (P < 0.05). FTIR results revealed significant peptide structure changes in USXY, USAR and USGA compared to other samples. USXY exhibited the highest Oxygen radical absorbance capacity (ORAC) value of 109.15 µg TE/mL, followed by USGA and USAR (94.07 and 93.41 µg TE/mL), respectively (P < 0.05). USXY and USAR showed different aroma features as compared to other MRP (P < 0.05). In addition, US enhanced umami, sweetness and sourness attributes and reduced bitterness of all MRP. USXY exhibited the highest umami intensity score (7.4), followed by USGA (7.3) and USAR (7.2), respectively. Partial least square regression analysis showed that the stronger umami taste was strongly correlated to aldehydes, thiophenes, MW 1000–3000 and 500–1000 Da peptides. Thus, US-assisted enzymatic hydrolysis and MR with xylose (XY) could be a promising way to produce natural flavouring with improved antioxidant activity.