食品体系组成及加工方式对植物次生代谢物生物利用度的影响研究进展

食用富含植物次生代谢物的食物能够调控人体健康,然而由于溶解性差、化学不稳定等因素,这些次生代谢物的生物利用度通常较低.食品加工导致的食品组成破坏是植物次生代谢物释放的重要条件,同时食品体系组成还会影响植物次生代谢物的吸收.本文综述了脂质和蛋白质等不同食品体系组成以及热处理、机械加工、发酵等食品加工方式对植物次生代谢物生...     

A cost and returns evaluation of alternative dairy products to determine capital investment and operational feasibility of a small-scale dairy processing facility

This study examines the economic feasibility of 50-and 500-cow dairy processing facilities for fluid milk, yogurt, and cheese. Net present value and internal rate of return calculations for projected costs and returns over a 10-yr period indicate that larger yogurt and cheese processing plants offer the most profitable prospects, whereas a smaller yogurt plant would break even. A smaller cheese plant would have insufficient returns to cover the cost of capital, and fluid milk processing at either scale is economically infeasible. Economic success in processing is greatly contingent upon individual business, financial management, and marketing skills.     

Fluid milk processing costs: current state and comparisons

An economic-engineering model is used to derive the theoretically minimum cost of processing and distributing fluid white milk for the state of Maine. This model represents a state-of-the-art milk processing facility and is used to evaluate three questions: 1) the components of total processing costs; 2) whether the cost of milk processing declines with increasing plant size; and 3) the minimum processing volume to financially justify inplant blow-molding technology. The model indicates that significant savings in per-container processing costs can be achieved by increasing plant size. However, distribution costs, related to the geographical distribution of consumer demand and plant location in the state of Maine do not favor large centralized plants. In addition, this model is compared with results published in 1993 to evaluate cost trends over a 7-yr period. The model indicates import shifts to more technologically advanced processing equipment and a dramatic increase in labor costs. Overall, processing costs have risen 2.9% annually above the rate of inflation. Dairies that are unable to respond to increased labor costs through capital investment and expansion will likely find it more difficult to remain competitive in the milk processing industry.     

Application of extrusion technology in plant food processing byproducts: An overview

The food processing industry generates an immense amount of waste, which leads to major concerns for its environmental impact. However, most of these wastes, such as plant‐derived byproducts, are still nutritionally adequate for use in food manufacturing. Extrusion is one of the most versatile and commercially successful processing technologies, with its widespread applications in the production of pasta, snacks, crackers, and meat analogues. It allows a high degree of user control over the processing parameters that significantly alters the quality of final products. This review features the past research on manufacture of extruded foods with integration of various plant food processing byproducts. The impact of extrusion parameters and adding various byproducts on the nutritional, physicochemical, sensory, and microbiological properties of food products are comprehensively discussed. This paper also provides fundamental knowledge and practical techniques for food manufacturers and researchers on the extrusion processing of plant food byproducts, which may increase economical return to the industry and reduce the environmental impact.     

亲水胶体对植物蛋白凝胶影响的研究进展

凝胶性作为植物蛋白重要的功能特性之一，对改善食品加工品质具有重要影响。但多数植物蛋白凝胶对pH、温度和离子强度等环境因素敏感，导致其凝胶制品存在黏结性不强、纹理结构差、成品率低等问题，在食品加工中的应用受到限制。亲水胶体具有较好的凝胶性、增稠性和稳定性，利用亲水胶体对植物蛋白凝胶进行改性，日益受到广泛关注。本文综述了植物蛋白和亲水胶体的凝胶机制，离子型、非离子型亲水胶体、复配亲水胶体与植物蛋白共混凝胶的性质，及温度、pH、离子强度、亲水胶体与蛋白比例及混合方式对亲水胶体-植物蛋白共混凝胶体系稳定性的影响，以期对植物蛋白凝胶制品加工与利用提供理论依据。     

Distribution of Listeria monocytogenes subtypes within a poultry further processing plant

Samples from environmental sites and raw product in a chicken further processing plant were collected every 6 weeks for 12 months. Each sample site was examined before and after a complete production shift. All samples were examined for the presence of Listeria monocytogenes, which was detected in floor drains on the raw product side of the plant preoperation and in drains on both raw and cooked sides following 8 h of processing operation. L. monocytogenes also was detected in raw product and once in fully cooked product but never on cooked product contact surfaces. One hundred sixty-one isolates were collected from 75 positive samples. All isolates were subtyped using a sequence-based method, and 14 unique subtypes were detected through the course of the study. Four of these types were found repeatedly and appeared to be resident in the plant. Three of the four resident strains were detected on raw product at some point during the year-long study, suggesting that raw product may be one source of L. monocytogenes in the processing plant environment. These data highlight the need for research to investigate why some types of L. monocytogenes persist in a processing plant environment but others do not.     

Modeling of fugitive dust emission for construction sand and gravel processing plant

Due to rapid economic development in Taiwan, a large quantity of construction sand and gravel is needed to support domestic civil construction projects. However, a construction sand and gravel processing plant is often a major source of air pollution, due to its associated fugitive dust emission. To predict the amount of fugitive dust emitted from this kind of processing plant, a semiempirical model was developed in this study. This model was developed on the basis of the actual dust emission data (i.e., total suspended particulate, TSP) and four on-site operating parameters (i.e., wind speed (u), soil moisture (M), soil silt content (s), and number (N) of trucks) measured at a construction sand and gravel processing plant. On the basis of the on-site measured data and an SAS nonlinear regression program, the expression of this model is E = 0.011.u2.653.M-1.875.s0.060.N0.896, where E is the amount (kg/ton) of dust emitted during the production of each ton of gravel and sand. This model can serve as a facile tool for predicting the fugitive dust emission from a construction sand and gravel processing plant.     

Molecular Detection of a Histamine Former, Morganella morganii, in Albacore, Mackerel, Sardine, and a Processing Plant

ABSTRACT: Testing for Morganella morganii , a prolific histamine former, was carried out in fish and processing plant to determine its origin and contamination source using PCR assay coupled with Southern hybridization. M. morganii was mostly found in mackerel and sardines but rarely in albacore. It was most frequently present in the gill followed by the skin but rarely in the intestine and cavity. No M. morganii was found in the processing plant but was detected on the surfaces of conveyer belts and plastic totes during processing. The compiled results indicated that histamine-forming bacteria are endogenous to fish and pointed out the importance of sanitation in the processing plant to prevent cross-contamination.     

Thermal, high pressure, and electric field processing effects on plant cell membrane integrity and relevance to fruit and vegetable quality

Advanced food processing methods that accomplish inactivation of microorganisms but minimize adverse thermal exposure are of great interest to the food industry. High pressure (HP) and pulsed electric field (PEF) processing are commercially applied to produce high quality fruit and vegetable products in the United States, Europe, and Japan. Both microbial and plant cell membranes are significantly altered following exposure to heat, HP, or PEF. Our research group sought to quantify the degree of damage to plant cell membranes that occurs as a result of exposure to heat, HP, or PEF, using the same analytical methods. In order to evaluate whether new advanced processing methods are superior to traditional thermal processing methods, it is necessary to compare them. In this review, we describe the existing state of knowledge related to effects of heat, HP, and PEF on both microbial and plant cells. The importance and relevance of compartmentalization in plant cells as it relates to fruit and vegetable quality is described and various methods for quantification of plant cell membrane integrity are discussed. These include electrolyte leakage, cell viability, and proton nuclear magnetic resonance (1H-NMR).     

植物蛋白肉的加工及品质特性研究进展

由于动物蛋白需求增加导致的环境压力增大、供给压力增大以及人体健康等问题,近年来植物蛋白肉受到国内外研究人员的广泛关注,成为食品行业的新风口。植物蛋白肉是以植物原料或其制品为蛋白质、脂肪的主要来源加工制成的具有与动物蛋白的质构、风味、形态等品质特征类似的替代肉制品。目前国内外已有多种加工方式来制备生产植物蛋白肉,但植物蛋白肉的品质与动物蛋白相比仍具有一定的差距,因此探究植物蛋白肉品质特性以及提升方法刻不容缓。本文总结了植物蛋白肉生产原料、加工技术及加工中的化学变化;阐述了植物蛋白肉的结构特性、质构及感官特性、营养特性等品质特性及分析评价方法;最后提出了改善植物蛋白肉品质的研究方向,以期为植物蛋白肉产品品质提档升级提供参考。     

Occurrence of Listeria monocytogenes in freshwater fish farms and fish-smoking plants

Three Swiss fish farms, farming rainbow trout (Oncorhynchus mykiss), and their affiliated smoking plants were analyzed for the presence of Listeria spp. 590 samples were collected from the farming environment (raceway water, sludge), faecal content and skin of the fish, fish during processing, and the processing environment.Listeria spp. were found at prevalences of 2·3% in plant A, 31·6% in plant B (mainly L. monocytogenes), and 13·8% in plant C (mainly L. innocua). This high contamination rate in plant B may be explained by the following facts: (i) farm B uses river water flowing through agricultural land; (ii) plant B rears fish in earth ponds instead of concrete ponds or raceways; (iii) fish from farm B had not been denied feed prior to slaughter; and (iv) total lack of regular mechanical and chemical cleaning in the fish farm B and processing plant B.In all three plants samples taken after smoking but before packaging did not contain Listeria spp., although in plant B and C the raw fish was contaminated. Hygienic defaults during packaging can lead to contaminated ready-to-eat products, detected in plant B (L. monocytogenes) and plant C (L. innocua) with one sample each. To minimize a possible health hazard to the consumer, it is of great importance to prevent postprocessing contamination of smoked fish.Finally, means of preventing Listeria contamination during farming, slaughtering, processing and storage are suggested.     

The microbial ecology of processing equipment in different fish industries-analysis of the microflora during processing and following cleaning and disinfection

The microflora adhering to the processing equipment during production and after cleaning and disinfecting procedures was identified in four different processing plants. A total of 1009 microorganisms was isolated from various-agar plates and identified. A stepwise procedure using simple phenotypic tests was used to identify the isolates and proved a fast way to group a large collection of microorganisms. Pseudomonas, Neisseriaceae, Enterobactericeae, Coryneform, Acinetobacter and lactic acid bacteria dominated the microflora of cold-smoked salmon plants, whereas the microflora in a plant processing semi-preserved herring consisted of Pseudomonas, Alcaligenes and Enterobactericeae. Psychrobacter, Staphylococcus and yeasts were found in a caviar processing plant. Overall, many microorganisms that are often isolated from fish were also isolated from the fish processing plants. However, some selection depending on processing parameters occurred, since halo- and osmo-tolerant organisms dominated in the caviar processing. After cleaning and disinfection, yeasts, Pseudomonas, Neisseriaceae and Alcaligenes remained in smokehouses, yeasts and Pseudomonas in the herring plant and Pseudomonas, Staphylococcus and yeasts in the caviar plant. The dominant adhering organisms after cleaning and disinfection were pseudomonads and yeasts independently of the microflora during processing. Knowledge of the adhering microflora is essential in the Good Hygienic Practises programme of food processing plants, as the development and design of improved cleaning and disinfecting procedures should target the microorganisms persisting and potentially contaminating the product.     

Release and absorption of carotenes from processed carrots (Daucus carota) using in vitro digestion coupled with a Caco-2 cell trans-well culture model

The release and absorption (bioavailability) of carotenoids is a prerequisite for their nutritional impact. This can be strongly affected by the processing conditions used to prepare the food matrix that contains them. To determine the effect of processing on carotenoid bioavailability, homogenized, raw, blanched and cooked carrots were exposed to an in vitro gastric and intestinal digestion model. Final digest samples were placed onto a Caco-2 cell trans-well monolayer culture to mimic intestinal absorption. The results show that the cooked carrot puree consisting of primarily single plant cell particles had the highest release of carotenes, followed by blanched consisting primarily of plant cell clusters and raw carrot puree consisting of larger plant cell clusters. Absorption through the Caco-2 cell layer was the highest from the digesta of cooked carrot puree followed by the digesta of blanched carrot puree. This study demonstrates that thermal processing and/or mechanical homogenization to disrupt plant cell wall matrix enhances the in vitro bioavailability of carotenes from carrots.     

植物多酚与淀粉的分子相互作用研究进展

淀粉是食品工业的重要原料之一,同时也是人体主要的供能物质。植物多酚是一类广泛存在于植物中且对人体健康有益的活性物质。植物多酚与淀粉的分子相互作用会影响淀粉基食品在加工和贮藏过程中的品质（如质构、风味及色泽等）及营养特性。本文在查阅和整理国内外有关文献和研究的基础上,对植物多酚与淀粉的分子相互作用及其对淀粉和植物多酚相关性质的影响进行综述,包括植物多酚与淀粉的复合物形成方式（以疏水作用力为主的V型复合物和以氢键为主的非V型复合物）,其相互作用对淀粉理化性质（糊化性质、回生性质和流变性质等）、微观结构和消化特性的改变及其对植物多酚的保护及缓释作用,以期为植物多酚在淀粉的加工、贮藏及其他相关领域的资源化利用提供有益的帮助与参考。     

现代生物技术在植物病原菌检测中的应用

植物病原菌根据形态观察的方法进行分类鉴定比较困难。综述了国内外关于现代生物技术在植物病原菌检测应用的最新成果,旨在促进我国植物病原菌研究的快速发展。     

Direct detection and identification of lactic acid bacteria in a food processing plant and in meat products using denaturing gradient gel electrophoresis

We established a novel system using denaturing gradient gel electrophoresis (DGGE) to quickly identify bacteria known to be responsible for spoilage in meat processing plants and meat products. We extracted bacterial DNA from swabbed samples at various locations in the plant and from meat products and performed PCR amplification, targeting 16S rDNA from the dominant organisms. The amplification products were subjected to DGGE, and the contaminating bacteria in the meat products and the plant were analyzed. This analysis indicated that lactic acid bacteria and spoilage-causing bacteria are widely distributed within the meat processing plant. We developed molecular size markers to identify the dominant organisms obtained from the plant and meat products. The establishment of the present method allows quick and simple identification of bacteria causing the possible deterioration of products and contamination and thus permits constant monitoring of any harmful bacteria within meat processing plants.     

Characterization of Listeria monocytogenes and Listeria innocua from a vegetable processing plant by RAPD and REA

The incidence of Listeria monocytogenes in a vegetable processing plant was investigated over a 23-month period. Frozen ready-to-eat vegetable samples, well as the plant environment, were sampled. The molecular subtyping techniques, Random Amplified Polymorphic DNA (RAPD) and Restriction Endonuclease Analyses (REA), were performed to help investigate the origin and routes of Listeria dissemination.

The low and sporadic incidence of L. monocytogenes made it impossible to establish an epidemiological sequence in the processing plant, though a case of cross-contamination between tomato and ratatouille was detected. Listeria innocua subtyping, however, allowed us to determine the prevalence of several strains in vegetables, and their presence on machinery samples suggested the possibility of cross-contamination during processing.

The low incidence of L. monocytogenes indicated that the risk of listeriosis transmission by vegetable consumption is low. On the other hand, the isolation of the same strain of L. innocua in several surveys pointed out the risk of colonisation on surfaces and machinery. The persistence of Listeria spp. is a cause for concern as can lead to future contamination of vegetables processed in the plant and to a possible increased risk for health. Therefore, periodic controls for the presence of Listeria spp. and a further review of the cleaning and disinfection procedures used in frozen vegetable plants are recommended.     

THE DESIGN OF COMPLETE ASEPTIC PROCESSING SYSTEMS

The paper shows the design development during the last decade of UHT plants in the United Kingdom. With the increase of automation in the dairy industry the progress in the design of aseptic processing systems leading to the simplification of the basic design is described in detail. Indirect and direct UHT plant are considered and the advantages and disadvantages of design evaluated. The operation of aseptic processing lines is discussed and the need for a high standard of experience in operators stressed. Variations in design of UHT plant and aseptic tank systems are examined with further development in the use of aseptic fillers.     

SIMULATION BASED PERFORMANCE ANALYSIS of CRAWFISH PROCESSING OPERATIONS1

A detailed model of crawfish processing operations was developed using the SLAM II simulation language. the simulation model was used to compare overall plant performance for two crawfish cooking schemes, boiling water and steam infusion, and to evaluate processing parameters for different plant capacities. For all the range of operating levels included in this study (2,400-19,000 lb of live crawfish/day or 360-2,900 lb of tail meat/day), the steam infusion cooking scheme rendered shorter processing times than those required by the boiling water cooking scheme. Moreover, the batch sizes and amount of resources used are smaller for the steam infusion cooking scheme. the simulation model is a valuable tool to analyze the performance of crawfish plants as well as to determine the impact of changes in technology on the overall process.     

促进植物内源性果胶甲酯酶催化作用的因素与机制及其在果蔬加工中的应用

植物内源性果胶甲酯酶（pectin methylesterase,PME）存在于天然植物组织中,可以催化高酯果胶脱甲基酯化生成低酯果胶,进而影响果蔬硬度、出汁率等质构及加工品质。一方面,为了避免贮藏期间出现果蔬汁浑浊沉淀、果蔬罐头中果肉变软、调味酱（如辣椒酱）中皮肉分离等不良品质,会在加工过程中抑制PME活性;另一方面,为了提高果蔬汁出汁率、生产低酯果胶等,也可在食品中添加外源PME。目前,对于通过激活内源PME来改善食品加工的研究较少,因此,本综述重点讨论促进植物内源性PME催化作用的因素与机制及其在果蔬贮藏加工中的应用,为植物内源性PME在果蔬加工中的充分利用提供理论参考。