Effects of high hydrostatic pressure on microstructure,physicochemical properties and in vitro digestibility of oat starch/β-glucan mixtures

Oats do not contain gluten protein, and oat dough structure is formed mainly through the hydrogen bonding of starch and β-glucan. As a non-thermal processing technology, high hydrostatic pressure (HHP) is mainly used to modify starch and protein in food processing. This study investigated the effects of HHP treatment on the morphological, structural, thermal, pasting and in vitro digestion properties of oat starch/β-glucan mixtures. Results showed that β-glucan interconnects with amylose through hydrogen bonding and has a protective effect on the crystalline region of oat starch. Effect of HHP treatment on the crystal structure of mixture system goes through crystal structure perfection stage, crystallisation disintegration and gelatinisation stage. After 300–400 MPa treatment, the changes in particle surface were not obvious, the phase transition temperature, the ΔH_gel and the PT of mixtures increased, while the particle size, viscosity and BD values decreased. After 500–600 MPa treatment, mixtures were completely gelatinised, most of the particles swelled and deformed, the particle size increased significantly. The principal component analysis results show that the complexes were distributed in the same region with similar properties after the 300–400 MPa and 500–600 MPa treatments, respectively.     

高静压对木薯淀粉理化特性及结构的影响

木薯原淀粉因存在不溶于冷水、易老化等诸多性质上的不足,极大地限制了其在食品、药品等领域的应 用。为了优化木薯淀粉的产品特性,通过对木薯淀粉进行高静压（200～600 MPa）改性处理,来优化其性质并拓 展其应用范围。结果显示高静压处理后木薯淀粉颗粒形貌发生明显变化,透光率、溶解度和膨润力均下降,老化值 增大,特别是在600 MPa改性处理后变化最明显,且失去偏光十字;此外,高静压处理后的木薯淀粉表观黏度低于木 薯原淀粉,剪切稀化现象更加明显。木薯原淀粉在经高静压处理后虽然晶型有一定的变化,但没有形成新的基团。     

Comparison of Microbial Inactivation and Rheological Characteristics of Mango Pulp after High Hydrostatic Pressure Treatment and High Temperature Short Time Treatment

The effects of high hydrostatic pressure (HHP) treatments at pressures of 300–600 MPa for 1–20 min and of high-temperature, short-time (HTST) treatment on the inactivation of natural microorganisms in blanched mango pulp (BMP) and unblanched mango pulp (UBMP) were investigated. No yeasts, molds, or aerobic bacteria were detected in BMP or UBMP after HHP treatments at 300 MPa/15 min, 400 MPa/5 min, 500 MPa/2.5 min, and 600 MPa/1 min and HTST treatment at 110 °C/8.6 s. Therefore, these conditions were selected to study the effects of HHP and HTST treatments on pectin methylesterase (PME) activity, water-soluble pectin (WSP) levels, and the rheological characteristics of UBMP and BMP. HHP treatment at a pressure of 600 MPa for 1 min significantly reduced PME activity in UBMP and significantly activated PME in BMP, whereas pressures of 300–500 MPa activated PME regardless of blanching. However, PME activity was reduced by 97 % in UBMP and was completely inactivated in BMP by HTST treatment. WSP levels were significantly decreased by HHP treatment but were increased by HTST treatment in UBMP and BMP. Both HHP and HTST treatments increased the viscosity, storage modulus, and loss modulus of UBMP and BMP. No significant changes in total sugar, total soluble solids, titratable acid, or pH were found after any treatment.     

高静压处理对黄桃罐头微生物和质构的影响

以黄桃罐头为试材,研究了高静压处理的杀菌效果,并用质地多面分析(TPA)方法,对高静压造成黄桃质构的变化进行分析。结果表明,400MPa下处理25min即可杀灭所有细菌,300MPa下处理15min就能杀灭所有霉菌和酵母菌。高静压处理(600MPa,5min)后黄桃罐头的硬度、凝聚性和咀嚼性与未处理无显著差异,但显著好于热处理。高静压技术能使黄桃罐头达到商业无菌,并保持良好质构。     

Effect of Osmotic Dehydration Under High Hydrostatic Pressure on Microstructure, Functional Properties and Bioactive Compounds of Strawberry (Fragaria Vesca)

Sliced strawberries were subjected to combined osmotic dehydration (40 °Brix) and high hydrostatic pressure (HHP) at 100, 200, 300, 400 and 500 MPa for 10 min. This research was carried out to study the effects of pressure on firmness, polysaccharides, total dietary fibre and microstructure, functional properties (rehydration ratio and water holding capacity) and bioactive compounds (anthocyanins, flavonoid and total phenolic). HHP affected the texture of the fruits leading to soft fruits due to increasing pressure. Fruit microstructure evidenced influence of pressure presenting the pressurised samples irregular matrices compared to samples treated at 0.1 MPa (control samples). Polysaccharides increased with pressure. Total dietary fibre, anthocyanins, flavonoids and total phenolic content showed a decrease with pressure when compared to control samples. Based on results, minor alterations of the mentioned quality parameters were evidenced when working in the range of 300–500 MPa.     

Effect of high hydrostatic pressure on starches: A review

Various strategies have been employed to enhance starch property, including thermal processing, chemical modification. The application of high hydrostatic pressure (HHP) may be a complementary, synergistic, or an additive starch enhancement technique. While most current applications of HHP are in starch processing, over 25 starches had been investigated by HHP, which can induce gelatinization and modification of some starches. Different starch responds differently to high pressure depending on the pressure range, starch source, pressurization temperature and time, different solvent and starch concentration. We have re‐examined the information on the various factors that influence the HHP‐induced structure, gelatinization, retrogradation, and modification of starches from different plant sources, with an emphasis on the HHP‐induced gelatinization. The compiled evidence of high pressure starch enhancement in this paper indicates that HHP is an effective technology with potential for greater utilization in starch application.     

Effect of high hydrostatic pressure on the quality-related properties of carrot and spinach

This study was designed to evaluate the potential effectiveness of high hydrostatic pressure (HHP) on the changes in quality-related properties of carrot and spinach as measured by ascorbic acid, carotenoids, phenols, flavonoids, microstructure, enzyme activity, and antioxidant activity. Better retention of ascorbic acid and carotenoids was observed at the carrots and spinaches treated at 100, 300, and 500 MPa for 20 min compared to the thermal processing. The color differences were noticeable at the carrot treated at 500 MPa (ΔE=3.5) and the spinach treated at 100 MPa (ΔE=3.6). The least residual peroxidase (POD) activity was 16.6% at the carrot at 300 MPa. The residual polyphenoloxidase (PPO) activities were decreased in carrot (15.1-6.9%) and spinach (31.1–21.3%) and the amounts of phenols flavonoids were increased with increasing pressure levels, leading to the enhanced antioxidant activity. Therefore, the HHP could be used as an alternative for improving quality of vegetables.

     

Effects of high hydrostatic pressure on physicochemical and functional properties of walnut (Juglans regia L.) protein isolate

BACKGROUND: Walnut (Juglans regia L.) is a good source of protein that has potential application in new product formation and fortification. The main objectives of this study were to investigate the effects of high hydrostatic pressure (HHP) treatment (300–600 MPa 20 min) on physicochemical and functional properties of walnut protein isolate (WPI) using various analytical techniques at room temperature. RESULTS: The results showed significant modification of solubility, free sulfhydryl content and surface hydrophobicity with increased levels of HHP treatment, indicating partial denaturation and aggregation of proteins. Differential scanning calorimetry and fluorescence spectrum analyses demonstrated that HHP treatment resulted in gradual unfolding of protein structure. Emulsifying activity index was significantly (P < 0.05) increased after HHP treatment at 400 MPa, but significantly decreased (P < 0.05) relative to the untreated WPI with further increase in pressure. HHP treatment at 300–600 MPa significantly decreased emulsion stability index. Additionally, HHP‐treated walnut proteins showed better foaming properties and in vitro digestibility. CONCLUSION: These results suggest that HHP treatment could be applied to modify the properties of walnut proteins by appropriate of pressure levels, which will help in using walnut protein as a potential food ingredient. © 2012 Society of Chemical Industry     

超高静压对非浓缩还原杨梅果汁中氧化酶的钝化作用

该研究以非浓缩还原（not from concentrate,NFC）杨梅果汁为研究对象,研究不同超高静压（high hydrostatic pressure,HHP）处理（300~600 MPa/0~30 min）对NFC杨梅汁中多酚氧化酶（polyphenol oxidase,PPO）和过氧化物酶（peroxidase,POD）的影响。对比传统高温灭酶,拟合建立HHP压力与酶活性的一级动力学回归方程,分析得到相关参数（压力脉冲效应PE、压力脉冲数值ND、等效破坏值Dp及酶的失活速率K）。结果表明,较高压力（400~600 MPa）对PPO与POD均起到钝化效果,其中600 MPa/10 min能钝化90%的PPO活性,600 MPa/20 min钝化80%的POD活性。600 MPa/30 min条件下,重复加压不能明显加强钝化效果。将PPO和PPO活性与压力进行一级动力学拟合,得到相应线性回归方程（R2>0.8）。随着压力从300 MPa升高到600 MPa,PPO的K值从3.03×10-2升高到12.12×10-2,POD的K值从1.23×10-3上升到7.67×10-3。600 MPa条件下,PPO和POD的ND分别为1.04和1.59,Dp值都为19。同时,压力和保压时间及其相互作用对PPO和POD活性的影响均有极高的显著性（p<0.001）。因此,HHP对杨梅果汁中关键的氧化酶能起到较好的钝化作用,能够为NFC杨梅汁加工技术的应用提供科学依据。     

Effects of high hydrostatic pressure (HHP) on protein structure and digestibility of red abalone (Haliotis rufescens) muscle

The protein secondary structure modifications and digestibility of red abalone muscle subjected to high hydrostatic pressure (HHP) treatments (200, 300, 400, and 500 MPa for 5 min) were evaluated. The protein structure was analysed by Fourier-Transformed Infrared spectroscopy. Protein digestibility was evaluated based on the degree of hydrolysis (DH) and peptide size distributions under in vitro gastrointestinal conditions. The intermolecular β-sheet structure was disrupted at 200 MPa, compensated by the formation of the intramolecular β-sheet. At 300 and 400 MPa, the β-sheet structure can fold on itself from the interactions that stabilize the protein structure. The 3₁₀-helix structure was significantly looser at 300 MPa. Structural modifications were accompanied by β-turn formation at 300, 400, and 500 MPa. In vitro gastrointestinal digestion is improved by HHP independently of pressure level. The results suggest that high pressure improve the DH of red abalone as a consequence of β-sheet and β-turn conformations changes.Industrial relevanceThe seafood industry uses high hydrostatic pressure (HHP) technology to reduce undesirable sensory changes and preserve the functional and nutritional properties of compounds. The HHP experiments contributed to unravel the impact of the different level pressure on digestibility. HHP treatment can change the secondary structures of proteins and improve the protein digestibility as function the pressure level. The results of this study provide valuable information for the potential application of HHP on the development of red abalone with high-nutritional value.     

高静压加工对新鲜蛋液微生物及品质的影响

研究在不同处理压力和时间条件下,高静压对新鲜全蛋液微生物(细菌总数、大肠菌群)、色泽、乳化特性(乳化活力、乳化稳定指数)及起泡特性(起泡性、泡沫稳定性)的影响。结果表明:200 MPa处理10 min,全蛋液微生物指标已符合国家标准;相比空白组,400 MPa处理10 min,全蛋液乳化活力及乳化稳定性显著增加,300 MPa处理20 min及400 MPa处理10 min全蛋液起泡性较好,而400 MPa处理10~15 min及500 MPa处理5~15 min可使全蛋液颜色更鲜亮。综上,适当的高静压处理可使全蛋液达到有效杀菌且改善其品质的目的。     

高静压处理对红薯淀粉颗粒结构的影响

淀粉颗粒结构研究是进行淀粉改性及拓宽其应用范围的基础。采用高静压对红薯淀粉进行改性处理,并 通过扫描电子显微镜观察、X射线衍射分析、傅里叶变换红外光谱分析、差示扫描量热分析及快速黏度分析探究不 同压力对淀粉颗粒结构的影响。结果显示,200～500 MPa高静压处理的红薯淀粉颗粒形貌无明显变化。600 MPa 处理后,淀粉颗粒开始塌陷并与周围颗粒凝聚,失去双折射现象;峰值黏度、谷值黏度和最终黏度分别显著升高 9.15%、27.18%和20.21%（P＜0.05）;糊化温度升高1.9 ℃,峰值时间延长1.16 min,但糊化焓和崩解值分别显著 降低46.18%和66.46%（P＜0.05）。此外,高静压处理后红薯淀粉分子基团和晶体类型保持不变。     

高静压对桃汁杀菌、钝化酶活性的效果

研究在不同处理压力和时间条件下,高静压加工技术对桃汁中微生物(细菌总数、霉菌、酵母菌、大肠菌群)以及酶(多酚氧化酶、果胶甲基酯酶、脂肪氧化酶)的影响。结果表明:经400MPa、5min高静压处理即可完全杀灭桃汁中的微生物;在400MPa和500MPa条件下,桃汁中的多酚氧化酶和脂肪氧化酶的活性出现了不同程度的激活现象,但在600MPa时,随着处理时间的延长,其活性逐渐降低,经30min处理后,分别被钝化了0.7662和0.641。而果胶甲基酯酶在400、500、600MPa条件下,出现了不规律的激活或钝化现象。另外,研究表明在高静压加工前增加漂烫工艺,可以有效杀灭桃汁中的微生物及钝化酶活性。     

超高压对马铃薯淀粉糊化作用的研究

采用偏光显微镜对超高压处理后的马铃薯淀粉偏光十字进行了观察,结果表明5%的马铃薯淀粉乳液在300、400、500 MPa下处理5 min后,马铃薯淀粉的偏光十字没有消失,在600 MPa下,少数淀粉颗粒的偏光十字开始消失,在700 MPa的超高压下处理5 min后,偏光十字全部消失,说明马铃薯淀粉糊化压力在600～700 MPa.     

超高压处理对养殖大黄鱼保鲜效果的影响

研究超高压处理对养殖大黄鱼保鲜效果的影响,经不同超高压（100、200、300、400、500 MPa,保压时间10、15 min）处理后,研究其pH值、aw、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、硫代巴比妥酸（thiobarbituric acid,TBA）值、三甲胺（trimethylamine,TMA）值、菌落总数的变化。其次,研究大黄鱼在4 ℃冷藏期间pH值、aw、TVB-N值、TBA值、TMA值、菌落总数的变化情况。结果表明,超高压处理后大黄鱼的pH值随着压力的升高而增加;aw随压力的升高而减小;TVB-N值随着压力的增加呈减小的趋势;TBA值随着压力的上升而增大;TMA值略有上升但幅度不大;菌落总数随压力增加明显降低。实验组的大黄鱼pH值和aw在4 ℃贮藏期先升后降;500 MPa、15 min 处理后45 d,大黄鱼的TVB-N值和TMA值增加,含量分别不超过35 mg/100 g和5 mg/100 g,TVB-N值和TMA值得到了有效控制;第45天500 MPa、15 min处理组大黄鱼的菌落总数为5.7×104 CFU/mL。因此,压强500 MPa保压时间15 min为养殖大黄鱼最适合的保鲜条件。     

Evaluation of the technological properties of rice starch modified by high hydrostatic pressure (HHP)

This aim of the study was to evaluate the technological properties of rice starch modified by high hydrostatic pressure (HHP). Black rice starch (BRS) was dispersed in 20% water and then HHP was applied at pressures of 200, 400 and 600 MPa for 30 min, where morphological, structural, functional and thermal parameters were evaluated. High pressure (BRS600) provided greater morphological damage, such as surface cavities and loss of crystallinity. The treatment HHP > 400 MPa the type of diffraction pattern was changed from type A to type V. The FT-IR spectra showed differences in intensity, especially for control, which revealed better defined peaks of greater intensity. The modified starch showed a greater affinity for water and oil absorption than the native starch as well as for milk absorption, exhibiting a higher binding capacity for the whole milk. HHP treatment is a fast and efficient non-thermal method to improve the technological properties of BRS.     

Effect of high hydrostatic pressure on modified noncrystalline granular starch of starches with different granular type and amylase content

Waxy corn (A-type pattern, amylopectin with trace amounts of amylase) and tapioca starch (C-type pattern, 17 g/100 g amylase content) were modified by High Hydrostatic Pressure (HHP) to produce noncrystalline granular (NCG) starch, respectively. The changes in the starch structure and properties occurring upon modified NCG after high-pressure treatment (300–600 MPa/30 min) were analyzed using polarized light microscopy (LM), differential scanning calorimetry (DSC), particle size distribution and scanning electronic microscopy (SEM). The resulting modified NCG starch took place when the 50 g/100 g starch suspension was treated under 450 MPa for the waxy corn starch with swelling degree of 57.07%, whereas 600 MPa for the tapioca starch with restricted starch swelling degree of 16.48%, indicating the stabilization effect of amylase. Also, they had reduced gelatinization temperatures, and lower pasting viscosities, which suggested that HHP had an effect on the physicochemical properties of native starch by destabilization, hydration and swelling.     

Effect of High Hydrostatic Pressure on Physicochemical and Structural Properties of Rice Starch

Rice starch–water suspension (20%) were subjected to high hydrostatic pressure (HHP) treatment at 120, 240, 360, 480, and 600 MPa for 30 min. Polarizing light microscope, scanning electron microscopy (SEM), rapid visco analyzer (RVA), differential scanning calorimeter (DSC), and X-ray diffraction were used to investigate the physicochemical and structural changes of starch. Microscopy studies showed that the treatment of starch with HHP under 600 MPa for 30 min resulted in a complete loss of birefringence and a gel-like appearance. The treatment of starch suspension with HHP at 600 MPa resulted in a significant increase in swelling power and solubility at low temperature (50–60 °C), but opposite trends were found at high temperature (70–90 °C). The DSC analysis showed a decrease in gelatinization temperatures and gelatinization enthalpy with increase of pressure levels. RVA viscograms of starches exhibited an increase in peak, trough, and final viscosities, peak time, and pasting temperature but decrease of breakdown, setback viscosities, and pasting temperature when pressure was increased. X-ray diffraction studies showed that the HHP treatment converted rice starch that displayed the A-type X-ray patterns to the B-type-like pattern. These results showed that the treatment of rice starch in 20% starch/water suspension at a pressure of 600 MPa for 30 min led to a complete gelatinization of starch granules.     

超高压对双孢蘑菇的杀菌效果和动力学的研究

以细菌总数、大肠菌群、酵母菌和霉菌数为对象,研究了超高压(High hydrostatic pressure,HHP)处理对双孢蘑菇(Agaricus bisporus)的杀菌效果和杀菌动力学。双孢蘑菇在300、400、500、600MPa压力下,室温下分别用HHP处理2.5～25min。结果表明:随压力的升高和时间的延长,杀菌效果增强;霉菌、酵母对压力较为敏感,400MPa处理2.5min可将其全部杀死;300MPa处理2.5min可完全杀灭双孢蘑菇中的大肠菌群。应用Weibull模型对不同处理条件下双孢蘑菇的杀菌效果进行拟合,拟合动力学曲线的决定系数R2均大于0.97,拟合效果较好。提出了双孢蘑菇的HHP杀菌的最优杀菌工艺参数,即600MPa处理5min,该条件即可以有效杀灭双孢蘑菇中的微生物。     

High hydrostatic pressure modification of whey protein concentrate for improved functional properties

Whey protein concentrate (WPC) has many applications in the food industry. Previous research demonstrated that treatment of whey proteins with high hydrostatic pressure (HHP) can enhance solubility and foaming properties of whey proteins. The objective of this study was to use HHP to improve functional properties of fresh WPC, compared with functional properties of reconstituted commercial whey protein concentrate 35 (WPC 35) powder. Fluid whey was ultrafiltered to concentrate proteins and reconstituted to equivalent total solids (8.23%) as reconstituted commercial WPC 35 powder. Solutions of WPC were treated with 300 and 400 MPa (0- and 15-min holding time) and 600 MPa (0-min holding time) pressure. After HHP, the solubility of the WPC was determined at both pH 4.6 and 7.0 using UDY and BioRad protein assay methods. Overrun and foam stability were determined after protein dispersions were whipped for 15 min. The protein solubility was greater at pH 7.0 than at pH 4.6, but there were no significant differences at different HHP treatment conditions. The maintenance of protein solubility after HHP indicates that HHP-treated WPC might be appropriate for applications to food systems. Untreated WPC exhibited the smallest overrun percentage, whereas the largest percentage for overrun and foam stability was obtained for WPC treated at 300 MPa for 15 min. Additionally, HHP-WPC treated at 300 MPa for 15 min acquired larger overrun than commercial WPC 35. The HHP treatment of 300 MPa for 0 min did not improve foam stability of WPC. However, WPC treated at 300 or 400 MPa for 15 min and 600 MPa for 0 min exhibited significantly greater foam stability than commercial WPC 35. The HHP treatment was beneficial to enhance overrun and foam stability of WPC, showing promise for ice cream and whipping cream applications.