Nonthermal Processes for Shelf‐Life Extension of Seafoods: A Revisit

For the past two decades, consumer demand for minimally processed seafoods with good sensory acceptability and nutritive properties has been increasing. Nonthermal food processing and preservation technologies have drawn the attention of food scientists and manufacturers because nutritional and sensory properties of such treated foods are minimally affected. More importantly, shelf‐life is extended as nonthermal treatments are capable of inhibiting or killing both spoilage and pathogenic organisms. They are also considered to be more energy‐efficient and to yield better quality when compared with conventional thermal processes. This review provides insight into the nonthermal processing technologies currently used for shelf‐life extension of seafoods. Both pretreatments such as acidic electrolyte water and ozonification and processing technologies, including high hydrostatic pressurization, ionizing radiation, cold plasma, ultraviolet light, and pulsed electric fields, as well as packaging technology, particularly modified atmosphere packaging, have been implemented to lower the microbial load in seafood. Thus, those technologies may be the ideal approach for the seafood industry, in which prime quality is maintained and safety is assured for consumers.     

Antimicrobial Effect of Malpighia Punicifolia and Extension of Water Buffalo Steak Shelf‐Life

In the present study, a multiple approach was used to characterize Malpighia punicifolia extract and to evaluate its inhibitory activity against several meat spoilage bacteria. First, volatile fraction, vitamins and phenolic compounds of the extract obtained by supercritical fluid extraction were determined by GC‐MS and HPLC. Then, the antimicrobial action of the extract was in vitro evaluated against Pseudomonas putida DSMZ 291^T, Pseudomonas fluorescens DSMZ 50009^T, Pseudomonas fragi DSMZ 3456^T, and Brochothrix thermosphacta DSMZ 20171^T by the agar well diffusion assay and by the agar dilution test. Based on the results of the minimum inhibitory concentration (MIC) against the assayed bacteria, 4 different concentrations of the extract were used in a challenge test on water buffalo steaks stored for 21 d at 4 °C. Results of chemical analyses showed that M. punicifolia extract is characterized by the presence of several compounds, already described for their antimicrobial (phenolic acids, flavonones, and furanes) and antioxidant (ascorbic acid) properties. The in vitro detection of antimicrobial activities highlighted that the extract, used at 8% concentration, was able to inhibit all the target bacteria. Moreover, very low MIC values (up to 0.025%) were detected. In situ tests, performed on water buffalo steaks treated with the extract in the concentration range 0.025% to 0.05%, showed a strong inhibition of both intentionally inoculated bacteria and naturally occurring microorganisms. Positive results, in terms of color and odor, were also observed during the entire storage of steaks preserved with the extract.     

Shelf‐Life Extension of Chill‐Stored Beef Longissimus Steaks Packaged under Modified Atmospheres with 50% O2 and 40% CO2

This study was conducted to compare the shelf‐life of beef steaks stored in different packaging conditions: overwrapped (OW) packaging and 2 modified atmosphere packaging systems (MAP): 80% O₂ MAP (80% O₂/20% CO₂) and 50% O₂ MAP (50% O₂/40% CO₂/10% N₂). Steaks were stored at 2 °C for 20 d. Headspace gas composition, microbial counts, color stability, pH, purge loss, and lipid oxidation were monitored. Among the packaging types, 50% O₂ MAP was superior to OW packaging and 80% O₂ MAP in delaying bacterial growth and extending shelf‐life to 20 d. 50% O₂ MAP also gave steaks an acceptable color during storage. No significant differences were observed in color stability of steaks packaged in both 50% O₂ MAP and 80% O₂ MAP. This study reveals 50% O₂ MAP is a realistic alternative to preserve beef steaks efficiently.     

Effect of High Hydrostatic Pressure Treatment (HHPT) on Quality and Shelf Life of Atlantic Mackerel (Scomber scombrus)

The ability of high hydrostatic pressure treatment (HHPT) to extend the shelf life of Atlantic mackerel (Scomber scombrus) was assessed in this study. For that purpose, fillets were subjected to pressure treatments at 200, 300, 400 MPa at 5, 10, 15 °C for 5 and 15 min. The influence of pressure treatments on the levels of trimethylamine nitrogen (TMA-N) and thiobarbituric acid (TBA) as well as color changes was investigated. The suitable combinations were determined as 200 MPa, 15 °C for 5 min. and 400 MPa, 5 °C for 5 min. In the second stage, the shelf life of samples, which were treated at these conditions, stored at 4?±?0.5 °C were studied by monitoring pH, color, sensorial features (appearance and odor), TMA-N, TBA, total volatile basic nitrogen, histamine, and total mesophilic aerobic count. The unpressurized mackerel samples were acceptable up to only 7 days compared to 17 and 19 days after 200 and 400 MPa treatments; respectively. The results obtained in this study showed that HHPT in combination with chilled storage can improve the shelf life and quality of fish.     

Compositional Analyses and Shelf‐Life Modeling of Njangsa (Ricinodendron heudelotii) Seed Oil Using the Weibull Hazard Analysis

This study investigated the compositional characteristics and shelf‐life of Njangsa seed oil (NSO). Oil from Njangsa had a high polyunsaturated fatty acid (PUFA) content of which alpha eleostearic acid (α‐ESA), an unusual conjugated linoleic acid was the most prevalent (about 52%). Linoleic acid was also present in appreciable amounts (approximately 34%). Our investigations also indicated that the acid‐catalyzed transesterification of NSO resulted in lower yields of α‐ESA methyl esters, due to isomerization, a phenomenon which was not observed under basic conditions. The triacylglycerol (TAG) profile analysis showed the presence of at least 1 α‐ESA fatty acid chain in more than 95% of the oil's TAGs. Shelf‐life was determined by the Weibull Hazard Sensory Method, where the end of shelf‐life was defined as the time at which 50% of panelists found the flavor of NSO to be unacceptable. This was determined as 21 wk. Our findings therefore support the potential commercial viability of NSO as an important source of physiologically beneficial PUFAs.     

高静压加工优化食品酶催化体系:现状与趋势

作为新兴的非热加工前沿技术,超高压食品加工已成为现代健康食品制造领域的研究热点.将其应用于优化食品酶催化体系,对指导现代食品生物加工具有重要意义.基于高静压加工优化食品酶催化体系研究已有几十年,将其成果加以总结,并分析存在的问题,有利于更好地促进现代食品加工的发展.本文综述了高静压加工优化食品酶催化体系的发展现状,分析提炼了科学问题,在此基础上提出本领域若干研究方向,期望能对相关领域研究者有所启发.     

Fresh‐Cut Onion: A Review on Processing,Health Benefits,and Shelf‐Life

The ready‐to‐eat produce market has grown rapidly because of the health benefits and convenience associated with these products. Onion is widely used as an ingredient in an extensive range of recipes from breakfast to dinner and in nearly every ethnic cuisine. However, cutting/chopping of onion is a nuisance to many consumers due to the lachrymatory properties of the volatiles generated that bring tears to eyes and leave a distinct odor on hands. As a result, there is now an increasing demand for fresh‐cut, value‐added, and ready‐to‐eat onion in households, as well as large‐scale uses in retail, food service, and various food industries, mainly due to the end‐use convenience. Despite these benefits, fresh‐cut onion products present considerable challenges due to tissue damage, resulting in chemical and physiological reactions that limit product shelf‐life. Intensive discoloration, microbial growth, softening, and off‐odor are the typical deteriorations that need to be controlled through the application of suitable preservation methods. This article reviews the literature related to the fresh‐cut onion, focusing on its constituents, nutritional and health benefits, production methods, quality changes throughout storage, and technologies available to increase product shelf‐life.     

气体结合高静压对预制莴笋货架期品质的影响

为了方便莴笋在人们日常生活中的摄入,满足人们对预制产品营养与品质的需求,采用高静压(High Hydrostatic Pressure,HHP,500 MPa,5 min)分别结合二氧化碳、氮气,以及抽真空体系处理新鲜莴笋,研究莴笋贮藏期间叶绿素含量、色泽、质构和微生物的变化。新鲜莴笋切丝烫漂30 s后称量包装热封,气体结合高静压处理后于4℃冷库中贮藏。结果表明:二氧化碳结合高静压处理后的鲜切莴笋货架期长达35 d,且叶绿素含量,色差CIE-L*a*b*值,质构,均优于氮气结合高静压组和真空结合高静压组,菌落总数低于其他两组。二氧化碳结合高静压能提高预制莴笋的贮藏品质并有效延长预制莴笋的货架期。     

Effect of High Hydrostatic Pressure (HHP) Treatment on Edible Flowers’ Properties

Edible flowers are increasing worldwide because they can improve the appearance, taste, and aesthetic value of food, aspects that the consumer appreciates. However, some of these are highly perishable and have a short shelf-life. To overcome these problems, high hydrostatic pressure (HHP) food processing might be applied, allowing producing high-quality food with enhanced safety and increased shelf-life. The application of HHP to vegetables has been extensively discussed and is already an industrial reality, but information on edible flowers is scarce and incomplete. Thus, in order to summarize the current knowledge on potential applications of HHP treatment in edible flowers and to determine the effect of this treatment on physical (e.g., color and texture) and nutritional characteristics as well as on microbial and enzymatic inactivation, a literature review was performed. It was stated that broccoli and cauliflower (inflorescences, usually not considered by consumers as flowers) have been the most studied, existing few information for other edible flowers. Thus, much more works are needed to better understand the effect and mechanisms behind HHP, and to define the adequate technological conditions for each flower.     

Effect of Single‐ and Two‐Cycle High Hydrostatic Pressure Treatments on Water Properties,Physicochemical and Microbial Qualities of Minimally Processed Squids (Todarodes pacificus)

This study investigated the effect of single‐ and two‐cycle high hydrostatic pressure (HHP) treatments on water properties, physicochemical, and microbial qualities of squids (Todarodes pacificus) during 4 °C storage for up to 10 d. Single‐cycle treatments were applied at 200, 400, or 600 MPa for 20 min (S‐200, S‐400, and S‐600), and two‐cycle treatments consisted of two 10 min cycles at 200, 400, or 600 MPa, respectively (T‐200, T‐400, and T‐600). HHP‐treated samples had higher (P < 0.05) content of P_2b (immobilized water) and P₂₁ (myofibril water), but lower P₂₂ (free water) than those of control. The single‐ and two‐cycle HHP treatments at the same pressure level caused no significant difference in water state of squids. The two‐cycle HHP treatment was more effective in controlling total volatile basic nitrogen, pH, and total plate counts (TPC) of squids during storage, in which TPC of S‐600 and T‐600 was 2.9 and 1.8 log CFU/g at 10 d, respectively, compared with 7.5 log CFU/g in control. HHP treatments delayed browning discoloration of the squids during storage, and the higher pressure level and two‐cycle HHP were more effective. Water properties highly corresponded with color and texture indices of squids. This study demonstrated that the two‐cycle HHP treatment was more effective in controlling microbial growth and quality deterioration while having similar impact on the physicochemical and water properties of squids in comparison with the single‐cycle treatment, thus more desirable for extending shelf‐life of fresh squids.     

Variations in lipid and fatty acid contents in different body parts of Black Sea whiting,Merlangius merlangus euxinus (Nordmann, 1840)

Whiting is a commercially important fish species of the world. This study demonstrates monthly variations in lipid and fatty acid (FA) contents of muscle, liver and roes of Black Sea whiting, Merlangius merlangus euxinus. Significant changes occurred in lipid contents between months (P < 0.05) with the highest values representing in liver 33.8–64.5%. Total polyunsaturated fatty acids (PUFA) in all groups were higher than total saturated and monounsaturated FAs with significant variations between months (P < 0.05). The highest PUFA of muscles, livers and roes were 60.0, 45.9 and 50.9%, respectively. The main FA was docosahexaenoic acid (DHA) of muscle tissue and roes, while oleic acid was the major FA in livers. Although about 164–357 g in muscle tissue or 224–392 g of whiting roe are necessary to consume to cover 1 g day^?1 of eicosapentaenoic acid (EPA)+DHA for a healthy diet, only as low as 5.5–10.0 g of liver would be enough to cover the same amount of daily EPA+DHA requirement. The results indicated that whiting livers constitute a rich and underexploited source of polyunsatured FAs. Furthermore, the results may aid further research on the nutritional studies, the physiology and stock management of whiting species.     

高静压酯化木薯淀粉结构及其理化性质的研究

研究将淀粉的酯化改性在高静压的协同作用下进行。选择木薯淀粉为原料,压力水平300、450及600 MPa,以醋酸酐为酯化剂,合成高静压酯化木薯淀粉。借助偏光显微镜、傅里叶红外光谱仪、粘度计、可见光分光光度计等分析手段,对其结构及理化性质进行系统研究。结果表明,红外光谱显示在1700 cm-1左右形成酯键,随着压力的升高偏光十字并没有明显的变化,说明形成的酯键使淀粉颗粒的晶体结构更加稳定,即使在600 MPa的高压下,淀粉颗粒的结构也不会明显的破裂。高静压协同酯化木薯淀粉的稳定性降低,抗酸性增强,变性淀粉相对原木薯淀粉而言抗老化性明显。450 MPa较300、600 MPa压力水平的冷、热粘度差值最大,其差值为27.56 m Pa·s。以上说明变性淀粉可以在造纸、纺织和化工等领域拥有更广阔的应用前景。     

高静压技术对豆浆中脂肪氧合酶的钝化效果及其动力学分析

研究了高静压技术(HHP)对豆浆中脂肪氧合酶(LOX)活性的钝化作用,并进行失活动力学分析。结果表明:HHP处理能显著钝化豆浆中LOX活性。用300～600MPa压力处理5～20min,对LOX活性有显著的钝化效果(P<0.05),并且随处理压力和处理时间的增加,酶的失活率提高。当压力500MPa,保压时间0min时也有一定的钝化LOX效果;当压力600MPa处理10min以上,豆浆LOX活性被完全抑制。用500MPa处理5min,可以达到与传统巴氏杀菌相同的钝酶效果(P>0.05)。HHP技术钝化豆浆LOX的过程可用一级动力学模型拟合(R2>0.900)。随着压力的升高和处理时间的延长,k值逐渐升高,D值逐渐减小;动力学参数ZP和Va分别为125.94MPa和-45.290cm3/mol。HHP技术在钝化豆浆中脂肪氧合酶活性方面比传统巴氏杀菌彻底,效果更好。其在改善豆浆品质方面具有良好的应用前景。     

Effect of High Hydrostatic Pressure (HHP) Treatment on Physicochemical Properties of Horse Mackerel (Trachurus trachurus)

The basic objective of this study was to determine the effect of high hydrostatic pressure (HHP; 220, 250 and 330 MPa), holding time (5 and 10 min) and temperature (7, 15 and 25 °C) on some quality parameters of horse mackerel such as colour changes, thiobarbituric acid (TBA-i) and trimethylamine nitrogen (TMA-N), free amino acid content. HHP increased L ^* values of horse mackerel. The a ^* and b ^* of treated horse mackerel did not change significantly after HHP applications. After, HHP, TBA-i and TMA values of all HHP-treated horse mackerel samples remained unchanged than those of untreated samples. The results obtained from this study showed that the quality of high pressure treated horse mackerel is best preserved at 250 MPa, 7–15 °C for 5 min, 220 MPa, 15–25 °C for 5 min, 250 MPa, 15 °C for 10 min and 330 MPa, 25 °C for 10 min.     

超高压对草莓果肉饮料的杀菌效果与品质影响

研究不同超高压条件(压力600MPa,保压时间分别为0、2、4、6、8、10min)对草莓果肉饮料的杀菌效果及600MPa、4min超高压处理前后草莓果肉饮料理化品质的变化。结果表明：在600MPa、4min的超高压条件下,草莓果肉饮料中的细菌、霉菌和酵母可全部被杀死,并且该处理前后草莓果肉饮料中的可溶性固形物、pH值、可滴定酸、颜色、总酚含量及抗氧化性均无显著性差异(P＞0.05),但VC含量损失9.2%、花青素含量损失20.6%;超高压处理后草莓果肉饮料中部分酯类成分损失,醇类物质种类及数量增加(P＜0.05),但仍保持草莓原有的特征风味。