Effects of CO2-assisted high-pressure processing on microbiological and physicochemical properties of Chinese spiced beef

The objective of this study was to evaluate the effect of CO₂-assisted high-pressure processing (CO₂-HPP) on microbiological and physicochemical properties of Chinese spiced beef. The presence of CO₂ induced extra reduction of Staphylococcus aureus, Escherichia coli and Listeria innocua under 150–450 MPa. The maximum extra reduction of S. aureus and E. coli were found at 450 MPa. The Listeria innocua cells were more resistant to CO₂-HPP than the Staphylococcus aureus and Escherichia coli cells. CO₂–450 MPa extended the shelf-life of Chinese spiced beef by one week than 450 MPa. CO₂–450 MPa didn't significantly increased the thiobarbituric acid reactive substances (TBARS) value of Chinese spiced beef compared with 450 MPa. CO₂–450 MPa limited 450 MPa induced color change. During cold storage, CO₂–450 MPa better maintained the firmness of Chinese spiced beef compared with 450 MPa, and the TBARS value of CO₂–450 MPa treated samples was significantly lower than 450 MPa-treated samples.Industrial relevanceHigh-pressure processing (HPP) is the most successful commercialized non-thermal technique in food industry, which could extend the shelf-life of Chinese spiced beef to 3 weeks. Nevertheless, HPP may induce color change, decrease firmness and increase lipid oxidation. Addition of carbon dioxide to HPP was shown to reduce lipid oxidation, limit color and texture changes, and slow down the growth of microorganisms in Chinese spiced beef during refrigerated storage. Our study determined the optimal condition. Furthermore, CO₂ inflation can be achieved with commercially available modified atmosphere packaging machine. When CO₂-HPP is industrialized, in addition to safety and nutrient preservation, the shelf-life of products will also increase.     

超高压处理对冷却牛肉色泽稳定性的影响

选取牛肉半腱肌为原料,研究室温条件下,常压以及200、400、600MPa超高压处理10min对牛肉色泽稳定性的影响,测定色差值、肌红蛋白含量、高铁肌红蛋白还原酶活性(MRA)、烟酰胺腺嘌呤二核苷酸(NADH)含量、耗氧率(OCR)等指标。结果表明:高压处理后牛肉的L*值升高,a*、b*值降低,OCR降低。MRA在400MPa左右达到最高,削弱高铁肌红蛋白(Met Mb)的积累,NADH含量与MRA相关。贮藏期间,各组MRA、NADH含量均降低,但高压处理组比对照组Met Mb积累速度慢,说明高压处理虽然可使肉色变浅,但贮藏期间肉色稳定性提高。      

超高压处理对冷却牛肉色泽稳定性的影响

选取牛肉半腱肌为原料,研究室温条件下,常压以及200、400、600MPa超高压处理10min对牛肉色泽稳定性的影响,测定色差值、肌红蛋白含量、高铁肌红蛋白还原酶活性(MRA)、烟酰胺腺嘌呤二核苷酸(NADH)含量、耗氧率(OCR)等指标。结果表明:高压处理后牛肉的L*值升高,a*、b*值降低,OCR降低。MRA在400MPa左右达到最高,削弱高铁肌红蛋白(Met Mb)的积累,NADH含量与MRA相关。贮藏期间,各组MRA、NADH含量均降低,但高压处理组比对照组Met Mb积累速度慢,说明高压处理虽然可使肉色变浅,但贮藏期间肉色稳定性提高。     

Effect of processing conditions on physicochemical properties of sodium caseinate-stabilized astaxanthin nanodispersions

The aim of the present study was to investigate the preparation of sodium caseinate-stabilized astaxanthin nanodispersions as potential active ingredients for food formulations in order to optimize processing conditions. Nanodispersions containing astaxanthin were prepared by an emulsification-evaporation processing technique. The influence of the processing conditions, namely, the pressure of the high-pressure homogenizer (20-90 MPa), the number of passes through the homogenizer (0-4) and the evaporation temperature (16-66 °C) on the physicochemical properties of the prepared astaxanthin nanodispersions were evaluated using a three-factor central composite design. Average particle size, polydispersity index (PDI) and astaxanthin loss in the prepared nanodispersions were considered as response variables. The multiple-response optimization predicted that using three passes through the high-pressure homogenizer at 30 MPa for the preparation of the astaxanthin nanoemulsion and then removing the organic phase (solvent) from the system by evaporation at 25 °C provided astaxanthin nanodispersions with optimum physicochemical properties.     

酱牛肉应力松弛特性实验

以5个品牌酱牛肉为试样,从压缩试验及应力松弛试验研究中获得力学-流变学性质参数,利用SPSS软件进行非线性回归拟合,建立了广义Maxwell流变模型。结果表明:酱牛肉具有良好的压缩黏弹性力学性质,属黏弹性材料,五元件广义Maxwell模型适用于模拟酱牛肉的应力松弛现象。对应力松弛参数做主成分分析,应力松弛试验的7个参数可以分为两个主成分,归纳为2类,即黏弹特性和松弛时间。     

Effect of high pressure processing on microbiological and physical qualities of carrot and spinach

This study was designed to evaluate the microbiological and physicochemical properties of carrot and spinach treated at 100, 300, and 500 MPa for 20 min. The numbers of Salmonella Typhimurium cells were significantly reduced by more than 5 log CFU/g in carrots and spinaches treated at 500 MPa after 5 min. The color changes were noticeable in the cooked carrots (ΔE>9) and spinaches (ΔE>12). Two distinct phases were observed in the textural changes of carrots and spinaches under high pressure processing. These results provide useful information for understanding microbial inactivation, color changes, and textural properties in high pressure-treated carrot and spinach samples.     

Effect of high hydrostatic pressure on physicochemical and biochemical properties of milk

Interest in high hydrostatic pressure (HHP) applications on milk and dairy products has recently increased as HHP offers a new technology for food preservation to the food industry. Although HHP-induced microbial destruction, rennet or acid coagulation of milk and increase in cheese yield has been reported, the actual effect of HHP application on milk constituents still remains to be unexplained. Therefore, we have analyzed the effect of HHP on physicochemical and biochemical properties such as turbidity, pH and especially protein micelle surface hydrophobicity of milk proteins. To serve for this purpose, milk samples with different fat contents were pressurized from 110 to 440 MPa at 25 °C for 10 and 20 min. Turbidity decreased with pressure increase and there was a slight change in pH. In order to measure the extent of exposure of hydrophobic groups of proteins to HHP, the method described by Bonomi et al. [1], based on use of a fluorescent probe, was utilized. In the light of the results obtained, it can be concluded that HHP has an effect on non-covalent interactions and especially hydrophobic bonds in milk. As the pressure is increased from 110 to 440 MPa, the micelles possibly decompose into sub-micelles and the embedded hydrophobic areas inside these micelles re-position in such a way that they can readily interfere with the fluorescent marker, ANS. These results may lead to practical applications of HHP treatment in the dairy industry to produce microbiologically safe, minimally processed products with high nutritional and sensory quality and novel texture.     

卤制工艺对湘味卤牛肉品质和风味的影响

目的：提升湘味卤牛肉品质、改进卤制工艺。方法：研究了脉冲卤制、真空卤制、微压卤制、传统卤制4种卤制工艺过程中牛肉品质和风味的变化规律。结果：随卤制时间延长,各卤制工艺牛肉的NaCl含量、烹煮损失率逐渐增加;色差L*值逐渐降低;咀嚼性、硬度、弹性先增加后降低;脉冲卤制、真空卤制、微压卤制、传统卤制感官评价最高得分分别为89.6,85.2,86.1,83.6,达到最高得分所需卤制时间分别为2.7,3.0,3.0,4.0 h,其中脉冲卤制感官评分最高,达至最高得分所需时间最少;在最高感官得分时,脉冲卤制牛肉的烹饪损失率为23.18%,低于微压卤制与传统卤制(P＜0.05),咀嚼性、硬度和弹性分别为5.15,11.21 N和0.782 mm,优于另外3种卤制工艺(P＜0.05);脉冲卤制牛肉的肌肉组织破坏程度最低,肌纤维间隙最大;脉冲卤制牛肉中月桂醛、桂酸乙酯、丁香酚等湘味卤制特征风味物质相对含量最高,为12.3%。结论：脉冲卤制最适合湘味卤牛肉生产,可有效提升湘味卤牛肉卤制效率、出品率与食用品质。     

Effect of high pressure processing on batters and cakes properties

High-pressure processing (HPP) is a novel non-thermal method that has shown great potential for reducing microbial loads, at temperatures below sterilization conditions. The aim of the present study was to investigate microbial, physical and structural changes in highly pressured batters and their layer cakes as a function of pressure level (300–600 MPa) and holding time (3–6 min). Characteristics of the batter (microflora, density, microstructure, and rheological properties) and cakes (specific volume, weight loss, color, and texture) were analyzed. HPP decreased molds and yeast and aerobic mesophilic bacteria counts, especially at highest pressures, and increased the density, G′, and G″ of batters. Cakes from HP treated batters presented a lower volume, darker crust, and harder texture than cakes from untreated batters. Increased values for the specific volume were obtained when the pressure was raised. Further studies are required to minimize its negative effects on the quality of the cakes.Industrial relevanceIn view of the increasing interest in home-made baking products, food industry has developed new commercially prepared batter products, which also present the disadvantage of a short shelf life even in cool conditions. High pressure processing (HPP) reduced microbial populations of batters, at temperatures below sterilization conditions. In this study, changes in the internal structure and the physical properties of batters and their consequences in the characteristics of cakes were also studied. These results showed negative effects of HPP in some batters constituents, so further studies are required to investigate possible changes in formulation, which reduce these effects.     

Cycled high hydrostatic pressure processing of whole and skimmed milk: Effects on physicochemical properties

In this study, we compare the effects of single- and double-cycle HP treatments at 600 MPa on inactivation of the natural microflora and physicochemical properties of whole and skimmed milk of high bacterial load. The results show that two-cycled HP (2 × 2.5 min) was more effective (P < 0.05) on microbial inactivation, and caused similar or slightly less changes (P > 0.05) in physicochemical properties of milk in comparison to single cycled HP (1 × 5 min). In addition to the expected milk protein structure changes, HP at 600 MPa caused only slight effects on milk fat and lactose. Minor decreases in levels of short chain fatty acids were observed with the cycled treatments, and the volatiles in general decreased after HP treatment, depending mostly on the pressure time but also on cycling in skimmed milk. The study confirmed the superior effect of two-cycle HP on microbial inactivation, and shows a slightly better preservation of the physical-chemical milk quality.Industrial relevanceMulti-cycling HP has been shown to be advantageous for microbial inactivation, but limited information is available regarding the effect on milk components in whole milk or skimmed milk. The present study compares the psychochemical properties of whole and skimmed milk processed by multi-cycling in comparison to single cycle HP treatment. Double cycled HP presented a superior effect on microbial inactivation and slightly better preservation of milk quality than one continuous HP.     

Effect of high hydrostatic pressure processing on the rennet coagulation kinetics and physicochemical properties of sheep milk rennet-induced gels

The effects of high hydrostatic pressure on the constituents and coagulation ability and their effect on cheese production of sheep milk have not been studied in detail. The objective of this work was to evaluate the effect of high hydrostatic pressure processing on the coagulation kinetics and physicochemical properties of sheep milk and to explore how such treatment could improve the cheesemaking process. Five batches of milk were tested: 1 untreated control batch and 4 batches each subjected to a different pressure (150, 300, 450, or 600 MPa) for 5 min at 10°C. As treatment pressure increased, values of electrical conductivity and oxidation-reduction potential were found to decrease. However, no significant reduction in pH was recorded. Treatment pressures >300 MPa produced milk with lower lightness (luminosity) and a more yellow and green hue. Pressures >150 MPa resulted in micellar fragmentation, as well as significant increases in particle size, viscosity, and water-holding capacity as a consequence of the denaturing of soluble proteins. High-pressure treatments increased the solubility of colloidal calcium phosphate, leading to a considerable increase in the concentration of minerals in the serum phase. The highest concentrations of calcium and phosphorus in the rennet whey of milk were reached at 300 MPa. Curd coagulation time was reduced by 28% at pressures >300 MPa, and an increase in the curd firming rate was observed. As treatment pressure increased to 450 MPa, the firmness, elasticity, and the percentage creep recovery of gels increased, whereas values of compliance and fracture strain were reduced. Thus, we can conclude that 300 MPa is the optimum treatment pressure for milk intended for cheesemaking by enzymatic coagulation. This pressure produced milk with optimal coagulation kinetics and water-holding properties with the least loss of fat and protein to the whey.     

超高压处理对小米粉理化特性的影响研究

对米水比例为1∶1、1∶2(w/w)的小米在600 MPa下分别处理15 min、30 min,探讨不同处理条件对小米粉理化特性的影响。结果表明：与空白组相比,超高压对4组不同样品小米粉颗粒形貌、粒径和晶体特性均有影响。全粉中淀粉颗粒形貌由分散的不规则球体变为与其他物质络合粘结成块结构,颗粒平均粒径显著降低,颗粒整体缩小,晶体结构由天然A型转变为B型,米水比为1∶2时对微观结构影响尤为显著。动态流变表明超高压处理后小米粉糊G’和tanδ均高于原粉,G’’均低于原粉,表明高压处理可提高小米淀粉弹性和黏性,该技术可作为有效的物理改性方法改善小米粉的物理特性。     

Effect of high pressure processing on the physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during iced storage

Scallops are the third largest aquaculture mollusks product, while they are highly perishable during storage. The main purpose of the present study was to evaluate the effect of high pressure processing (HPP) on physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during refrigeration storage. The scallop adductor muscle was treated with different pressures (200, 300, 400 and 500 MPa, 5 min) and iced storage for 28 days. Results showed that HPP delayed microbial growth as pressure increased. HPP (≥400 MPa) resulted in myosin and actin denaturation, increased hardness, whiteness, pH and promoted water migration. However, preliminary sensory analysis showed no significant difference between pressure-treated and control adductor muscles in appearance, odour, texture and overall acceptability after cooking. In addition, pressure-treated adductor muscles (≥300 MPa) remained edible after 28 days of storage. Overall, these results can provide basic knowledge for the storage of pressure-treated scallop meat.     

Effect of high pressure treatment on the physicochemical and functional properties of egg yolk

The effects of high-pressure (HP) treatment at 100–500 MPa on some physicochemical and functional properties of egg yolk (EY) were investigated. Protein solubility, viscosity, surface hydrophobicity (H₀), free sulfhydryl (SH) content, differential scanning calorimetry characteristics, emulsifying activities and emulsifying stability were evaluated. HP-treatment resulted in protein aggregation, as evidenced by gradual decrease in protein solubility and significantly increased in viscosity. HP-treatment at 100–500 MPa induced a gradual decrease in H₀ and SH content, possibly due to protein unfolding and subsequent aggregation/re-association of unfolded proteins. Emulsifying activity index (EAI) was slightly decreased between 100 and 300 MPa and when the pressure is above 400 MPa, EAI was significantly (P < 0.05) decreased relative to the untreated EY. HP-treatment at 100 MPa significantly (P < 0.05) increased the ESI values of EY, while a significant (P < 0.05) decrease was observed when the pressure was above 200 MPa. It was also investigated that there are significant correlations between physicochemical properties of EY, and the differences in the modification of EY protein by HP treatment at different pressure levels may be attributed to the differences in aggregation and unfolding/refolding extents of proteins.     

超高压对峰甘板栗风味物质及理化性状的影响

目的研究超高压(UHP)处理对峰甘板栗风味成分及理化性状的影响,对其感官品质评价提供数据支撑。方法将峰甘板栗分别在200、300、400和500 MPa条件下16℃保压10 min,采用超临界CO_2流体萃取(SCFE)技术对其进行提取,采用气相色谱-质谱方法(GC-MS)检测其风味成分的变化及测定各理化指标。结果在200~500 MPa条件下峰甘板栗风味物质分别保留了89.98%、36.86%、7.63%、40.38%;经过超高压处理,峰甘板栗中酯类、醇类物质的种类及含量均下降,而酮类和酸类化合物均有所增加。随着压力增加,峰甘板栗褐变度、硬度、可溶性总糖和水分含量都呈现不同程度的增长趋势。结论在峰甘板栗微生物数量不超过卫生安全限量前提下,300 MPa处理对峰甘板栗理化性状影响较小,风味保持较好,且新增加的风味物质对感官品尝具有积极作用,其感官质量评价较高。     

Effect of high hydrostatic pressure pretreatment on flavour and physicochemical properties of freeze-dried carambola slices

Ripe carambolas are hard to store and transport, while freeze-dried ones are easy to store. However, its long production time leads to higher costs. This study shows that high hydrostatic pressure (HHP) treatment could shorten the freeze-drying time of carambola slices. After HHP treatment (25–250 MPa), the drying time of the fresh sample can be shortened by 33.3–44.4% and the distribution of water and pigment in tissues is much uniform. With the increment of the pressure, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging rate are increased. At 250 MPa, the total phenolic content (TPC) increased from 11.34 to 13.36 mg GAE g⁻¹, and the total flavonoid content (TFC) of the control sample was increased from 10.77 to 12.73 mg RE g⁻¹. Compared with the untreated sample, HHP treatment can enhance the flavour and shorten the freeze-drying time. This work guides the application of HHP technology for drying food processing.     

Effect of high pressure processing on structural and functional properties of canned aquafaba

Food Science and Biotechnology - Aquafaba is chickpea cooking water. It has great functional properties since it consists of starch and protein. High pressure processing (HPP) is proven to modify...     

超高压技术在酱牛肉保鲜中的应用

为探究超高压技术应用于肉制品保鲜中的可行性,对真空包装的酱牛肉采用600MPa,5、10、15min的超高压处理并与热处理(85～90℃,10min)及未处理组对照,分别在0、2、4、6、8周测定了4℃冷藏条件下的菌落总数、乳酸菌数以及pH、色泽、脂肪氧化值、挥发性盐基氮等理化指标。结果表明,高压处理能够显著降低酱牛肉的初始菌数(p<0.05),抑制细菌的生长,5min和10、15min组分别在第4、第6周超过80000cfu/g;处理组均出现脂肪氧化值升高的现象,高压组pH略有升高,热处理组储藏末期红度值显著降低(p<0.05),其他理化指标没有显著变化。综合考虑,超高压技术可用于真空包装酱牛肉的保鲜中,延长产品货架期。