响应面法优化小米甜醅的制作及货架期预测

以小米为原料,研究发酵工艺条件,建立货架期预测模型。利用单因素试验和响应面试验得到最佳的生产条件:接种量1.9 g/kg、发酵温度23.5℃、发酵时间94.5 h。最终的产品感官评分36.9,还原糖含量23 g/100g,总酸含量16 g/kg。以菌落总数为指标,根据一级反应动力学方程和Arrhenius方程建立货架期预测模型,活化能Ea=28.00 KJ/mol,产品在4℃贮藏时保质期为24 d。     

Postharvest shelf life extension of blueberries using a biodegradable package

Small berries are commonly packaged and sold to consumers in vented petroleum-based clamshell containers. Biodegradable and compostable packages may be used as an alternative package to reduce waste generation and landfill disposal. In addition, the current clamshell container design does not allow the development of a modified atmosphere that could prolong berry shelf life. Thus, in this study, a non-ventilated biodegradable container was evaluated as a possible alternative to the containers normally used in commercial distribution of small berries. To determine the potential of biodegradable containers for small berries, highbush blueberries were packaged in polylactide (PLA) containers and stored at 10 °C for 18 days and at 23 °C for 9 days. Commercial vented clamshell containers were used as controls. Physicochemical and microbiological studies were carried out in order to compare the efficacy of both packages. Results showed that the PLA containers prolonged blueberry shelf life at different storage temperatures.     

酸奶的质量控制与延长货架期的研究

酸奶在我国的产品标准中要求必须含有活性乳酸菌,因此其运输、销售需要有良好的冷链系统来保证质量,为了延长酸奶的保质期,扩大酸奶的销售区域,针对酸奶的酸度、稳定剂的筛选、发酵剂的选择、钙盐用量的选择、杀菌技术进行研究.结果表明:稳定剂为藻酸丙二醇酯可防止杀菌过程中乳清析出,添加量为0.2%:钙离子对乳体系的稳定性起稳定的作用,添加量为0.1%,可达到基本没有乳清析出的效果.在特定温度下处理5 min～10 min可以使酸奶在贮存期间酸度保持稳定,同时,采取温和的杀菌温度可有效改善酸奶后酸化现象.酸奶低温贮存可有效延长货价期,密封保存的酸奶最佳保质期为3周.     

Blending response surface methodology and principal components analysis to match a target product

Highly trained sensory panels have long been used to evaluate food products on perhaps dozens of attributes. Principal components analysis is one of a number of multivariate data analysis techniques commonly used in analyzing sensory panel data. More recently, response surface designs have been used to direct the creation of product prototypes so that the effects of ingredient levels and/or processing conditions can be modeled. This paper will discuss how the two methodologies have been used together in projects where the goal is to identify ingredient levels and/or processing conditions that best match a target product's sensory profile. Some unique problems arise when analyzing and interpreting the results of response surface models when the number of responses is quite large. This paper will explain how some of these problems have been addressed through the detailed discussion of the development of a cost reduced product. Six ingredients were systematically varied in a response surface design to create 48 prototypes. The prototypes and the target product were then measured on 33 sensory attributes. Design selection, data collection, response surface modeling, rotated principal components analysis and the use of both desirability and distance functions to identify ingredient level combinations that meet the product development objectives will be discussed in detail using the data analyses from this project. Recommendations for next steps in the product development process will also be given.     

Development of shelf stable pepper based appetizers by response surface methodology (RSM)

The paper deals with three pepper-based appetizers developed in the form of convenient beverage mixes. The optimization of ingredients in the formulations of spiced drink mix, spiced tomato mix and chakota soup mix was achieved using response surface methodology with statistical design software. The active ingredient pepper was 1.5 and 2.8/100 g as black pepper and 9/100 g as white pepper with total pungency (expressed as piperine, g/100 g) of 0.08, 0.155, 0.155 in spiced drink mix, chakota soup mix and spiced tomato mix, respectively. The appetizer mixes packed in paper/Al foil/ polythene (PFP) and polypropylene (PP) pouches were stored at ambient temperature as well as 37 °C. Periodic evaluation (2-months interval) revealed that spice drink mix and spiced tomato mix had a shelf life of 6 months, while it was 8 months for chakota soup mix packed in PFP pouches under ambient conditions (18-33 °C).     

响应面法优化苹果渣生产细菌纤维素培养基及产物性能研究

为提高木醋杆菌（Acetobacter xylinum）发酵苹果渣水解液生产细菌纤维素（Bacterial cellulose,BC）的产量,采用响应面法对发酵培养基进行优化,同时利用傅里叶红外光谱（FT-IR）和X-射线衍射（XRD）对发酵产物BC的性能和结构进行比较。单因素及响应面实验结果确定木醋杆菌（Acetobacter xylinum）发酵苹果渣水解液生产BC的最佳培养基配方为:蔗糖38.44 g、蛋白胨10.91 g、硫酸镁0.85 g、黄嘌呤0.87 g、乙醇10 m L、苹果渣水解液1000 m L、p H6.0,在此条件下BC的产量为7.19 g/L,较优化前（5.65 g/L）提高了27.3%。苹果渣水解液发酵产物BC结构性能与基本培养基发酵产物BC基本一致。说明苹果渣能够替代部分发酵原料发酵生产BC,且不影响BC性能。      

Sweet potato-based pasta product: optimization of ingredient levels using response surface methodology

Sweet potato flour was used for the development of a pasta product. The system known as response surface methodology was used to analyse the effect of sweet potato flour, soyflour, water, Arabic gum and carboxy methyl cellulose (CMC) on quality responses (sensory, solids loss and hardness) of the pasta product. A rotatable central‐composite design was used to develop models for the responses. Responses were affected most by changes in soyflour and gum levels and to a lesser extent by sweet potato flour and water levels. Individual contour plots of the different responses were superimposed and regions meeting the maximum sensory score (33.8), minimum solids loss (16.6%) and maximum texture hardness (5616 g) were identified at 674 g kg^?1 sweet potato flour, 195 g kg^?1 water, 110 g kg^?1 soyflour, 10.6 g kg^?1 Arabic gum and 10.1 g kg^?1 CMC levels.     

Spoilage and shelf‐life extension of fresh fish and shellfish

Fresh fish and shellfish are highly perishable products due to their biological composition. Under normal refrigerated storage conditions, the shelf life of these products is limited by enzymatic and microbiological spoilage. However, with increasing consumer demands for fresh products with extended shelf life and increasing energy costs associated with freezing and frozen storage, the fish‐processing industry is actively seeking alternative methods of shelf life preservation and marketability of fresh, refrigerated fish and at the same time economizing on energy costs. Additional methods that could fulfill these objectives include chemical decontamination, low‐dose irradiation, ultra‐high pressure, and modified atmosphere packaging (MAP). This review focuses on the biochemical and microbiological composition of fresh fish/shellfish, the spoilage patterns in these products, factors influencing spoilage, and the combination treatments that can be used in conjunction with refrigeration to extend the shelf life and keeping quality of fresh fish/shellfish. The safety concerns of minimally processed/MAP fish, specifically with respect to the growth of Clostridium botulinum type E, is also addressed.     

Use of images in shelf life assessment of fruit salad

Fruit salads stored for different lengths of time as well as their images were used to estimate sensory shelf life by survival analysis. Shelf life estimates obtained using fruit salad images were longer than those achieved by analyzing the real product. This was attributed to the fact that images are 2-dimensional representations of real food, probably not comprehensive of all the visual information needed by the panelists to produce an acceptability/unacceptability judgment. Images were also subjected to image analysis and the analysis of the overall visual quality by a trained panel. These indices proved to be highly correlated to consumer rejection of the fruit salad and could be exploited for routine shelf life assessment of analogous products. To this regard, a failure criterion of 25% consumer rejection could be equivalent to a score 3 in a 5-point overall visual quality scale. PRACTICAL APPLICATION: Food images can be used to assess product shelf life. In the case of fruit salads, the overall visual quality assessed by a trained panel on product images and the percentage of brown pixels in digital images can be exploited to estimate shelf life corresponding to a selected consumer rejection.     

Effectiveness of active and modified atmosphere packaging on shelf life extension of a cheese tart

This study evaluated the shelf life extension of a cheese cake subjected to modified atmosphere (MAP) and active packaging (AP). Cheese cakes were packaged under different N₂/CO₂ ratios (70/30 and 20/80) (MAP batches), by placing a sachet of an iron oxide-based oxygen absorber inside trays (AP batch) and with air (air batch). Changes in microbial growth, in-package gas composition, chemical–physical parameters including texture and sensory attributes were monitored for 48 days at 20 °C. AP allowed a mould-free cheese cake shelf life of 48 days, MAP extended the shelf life of samples packaged under 30% and 80% CO₂ up to 14 and 34 days, respectively, whereas tarts stored with air spoiled after 7 days. MAP resulted in a significant increase in hardness after 14 days of storage, whereas AP tarts recovered the initial texture after 48 days. Panellists judged AP tarts over the acceptability threshold during the whole shelf life of cheese tarts.     

Use of chitosan to prolong mozzarella cheese shelf life

This study was undertaken to evaluate the feasibility of using chitosan, a natural antimicrobial substance, to improve the preservation of a very perishable cheese. The effectiveness of chitosan to inhibit the growth of spoilage microorganisms in Mozzarella cheese was studied during refrigerated storage. A lactic acid/chitosan solution was added directly to the starter used for Mozzarella cheese manufacturing. Mozzarella cheese samples were stored at 4°C for about 10 d and microbial populations as well as the pH were monitored. Results demonstrated that chitosan inhibited the growth of some spoilage microorganisms such as coliforms, whereas it did not influence the growth of other microorganisms, such as Micrococcaceae, and lightly stimulated lactic acid bacteria.     

Novel approaches for chemical and microbiological shelf life extension of cereal crops

Abstract

Economic losses due to post-harvest fungal spoilage and mycotoxin contamination of cereal crops is a frequently encountered issue. Typically, chemical preservatives are used to reduce the initial microbial load and the environmental conditions during storage are controlled to prevent microbial growth. However, in recent years the consumers’ desire for more naturally produced foods containing less chemical preservatives has grown increasingly stronger. This article reviews the latest advances in terms of novel approaches for chemical decontamination, namely application cold atmospheric pressure plasma and electrolyzed water, and their suitability for preservation of stored cereal crops. In addition, the alternative use of bio-preservatives, such as starter cultures or purified antimicrobial compounds, to prevent the growth of spoilage organisms or remove in-field accumulated mycotoxins is evaluated. All treatments assessed here show potential for inhibition of microbial spoilage. However, each method encounters draw-backs, making industrial application difficult. Even under optimized processing conditions, it is unlikely that one single treatment can reduce the natural microbial load sufficiently. It is evident that future research needs to examine the combined application of several treatments to exploit their synergistic properties. This would enable sufficient reduction in the microbial load and ensure microbiological safety of cereal crops during long-term storage.     

Development and application of a predictive model of Aspergillus candidus growth as a tool to improve shelf life of bakery products

Molds are responsible for spoilage of bakery products during storage. A modeling approach to predict the effect of water activity (a_w) and temperature on the appearance time of Aspergillus candidus was developed and validated on cakes. The gamma concept of Zwietering was adapted to model fungal growth, taking into account the impact of temperature and a_w. We hypothesized that the same model could be used to calculate the time for mycelium to become visible (t_v), by substituting the matrix parameter by t_v. Cardinal values of A. candidus were determined on potato dextrose agar, and predicted t_v were further validated by challenge-tests run on 51 pastries. Taking into account the a_w dynamics recorded in pastries during reasonable conditions of storage, high correlation was shown between predicted and observed t_v when the a_w at equilibrium (after 14 days of storage) was used for modeling (A_f = 1.072, B_f = 0.979). Validation studies on industrial cakes confirmed the experimental results and demonstrated the suitability of the model to predict t_v in food as a function of a_w and temperature.     

响应面法在静电纺丝中的应用

响应面法是一种解决多变量问题的统计方法,论述了响应面法的基本理论、试验设计和建模优化流程.将响应面法应用于存在非线性规律的多影响因素的静电纺丝过程,可以寻求最优工艺参数,有效地预测纤维直径,对静电纺丝工艺参数的控制、设备制造和产业化具有重要意义.     

响应面优化超声辅助提取甜菜红色素及稳定性研究

为了充分合理利用甜菜红色素资源,采用响应面优化了超声辅助提取甜菜红色素的工艺条件并对甜菜红色素的稳定性进行研究。响应面建立的模型数据拟合效果很好(R2=0.9401,Pr=0.001),优化所得最佳提取工艺参数为:超声时间55min、料液比1∶4.1g/m L、超声温度53℃、p H 4.4。甜菜红色素的稳定性研究结果表明:甜菜红色素应避光保存,Ca2+、Na+、Al3+、Mg2+等金属离子对甜菜红色素的稳定性影响微小,Fe3+和Cu2+严重影响甜菜红色素的稳定性,甜菜红色素适宜保存的p H范围为3~7,常用食品添加剂对甜菜红色素稳定性基本无影响。     

蜂胶提取液对猪肉保鲜效果的研究

研究不同浓度蜂胶提取液对鲜猪肉的保鲜效果。以猪肉的感官指标、挥发性盐基氮值、色差a＊值作为判定标准比较不同浓度蜂胶提取液在不同处理方法（涂抹、浸泡）和贮藏温度下的保鲜效果。结果表明,在蜂胶提取液浓度为0.015g/mL时采用涂抹法,对猪肉的保鲜效果最好,在37℃条件下可保鲜贮存24h,在0～4℃条件下可保鲜贮存12d以上。