微波处理对芝麻出油率及油脂品质的影响

对芝麻油料进行微波处理,选择微波功率、微波时间、增湿比例、缓苏时间为影响因素,饼残油率为考察指标,进行单因素实验,再在单因素实验结果基础上,进行正交实验,确定最佳微波条件,最后对比未经微波处理和最佳条件微波处理后所得油脂的品质。结果表明,微波处理能够提高芝麻出油率,且微波处理能够提高油中芝麻素和芝麻林素的含量,但对芝麻油的色泽、碘值、酸值、主要脂肪酸含量影响不大。微波处理后芝麻油的过氧化值会提高,但其含有的芝麻素、芝麻林素等抗氧化物质会使其氧化稳定性提高。微波处理油料可用作油料的预处理。     

Microwave heating of apple mash to improve juice yield and quality

The effects of four heat treatments of apple mash on juice yield and quality were evaluated and compared to juice produced from unheated apple mash at 21°C. Fuji and McIntosh apple mashes were heated to bulk temperatures of 40°C, 50°C, 60°C and 70°C in a 2450 MHz microwave oven at 1500 W. Juice yield increased when mash was heated before pressing. Cider produced from the heated mashes had comparable pH, titratable acidity, and sensory characteristics to cider produced from room temperature mashes; however, total phenolic and flavonoid content of the juice increased with increasing mash temperature. Soluble solids and turbidity also increased as treatment temperature increased.     

发酵控制系统如何提高啤酒质量

<正> 要提高啤酒的质量和生产效益,途径有很多,其中的发酵控制系统(Fermenting-Control-System)能使啤酒的发酵达到最佳化,在提高最终啤酒质量的同时,大大提高了生产效益,本文将详细剖析其运作模式。 原料质量的监控 用以生产啤酒的原料主要来自天然或农业产物,故其质量难免会出现季节性或地区性的波动,从而影响工艺的运作和最终产品的质量。观察发酵图就能立即发现潜在的发酵问题,再通过调整糖化和发酵程序,即能及时并有效地解决这方面的问题。     

酶法洗渣提高橙汁得率

研究酶法洗渣提高橙汁得率的新工艺。确定了酶法处理橙渣的工艺条件为:加酶量0.01%、渣水比1∶1、酶解温度45℃、酶解时间50min。实验证明,采用此法生产的橙汁能够明显提高出汁率和改善橙汁的产品质量,从而生产出具有良好的混浊稳定性、口味宜人、鲜艳色泽的橙汁。     

Effect of pretreatment with microwaves on mechanical extraction yield and quality of vegetable oil from Chilean hazelnuts (Gevuina avellana Mol)

The effect of microwave (MW) radiation on hazelnut seed (Gevuina avellana Mol) was studied as a substrate pretreatment prior to oil extraction by pressing. Samples were MW-treated at a frequency of 2450 MHz using a microwave oven. Six MW pretreatments were established, combining two potencies (400 W and 600 W) and three times of pretreatment (120, 180 and 240 s). Extraction oil yield increased with MW pretreatments of hazelnut seed with respect to untreated seeds, as a control. Conditions of 400 W and 240 s were selected (45.3% of extraction oil yield). Observations under light microscopy showed that the microstructure of treated samples to 400 W and 240 s, was modified comparing with that of untreated samples, thereby improving the extraction efficiency. The quality characteristics (e.g. acid value, peroxide value), oil composition (e.g. fatty acids, α-tocotrienol content) and oil oxidative stability (e.g. induction time) were measured. These results were compared to those of an untreated oil sample. MW pretreatment had a positive effect on oxidative oil stability (induction time of 23.9 h) with respect to untreated oil (8.8 h).

Industrial relevance

Chilean hazelnut (Gevuina avellana Mol) is the southernmost Macadamieae species of the family Proteaceae that grows mainly in the southern part of Chile and Argentina. The oil is composed mainly of unsaturated fatty acids, which represent 93% of the total. Its main components are oleic and palmitoleic acids, which represent 70% fatty acids. Conventional vegetable oil extraction is carried out by pressing or solvent extraction. Solvent oil extraction is the most efficient method; however, its application presents some industrial disadvantages such as plant security problems, emissions of volatile organic compounds into atmosphere, high operation costs and poor quality products caused by high processing temperatures. Mechanical pressing oil extraction is technically less extensive and less labor-intensive than the extraction solvent method . The safety and simplicity of the whole process is advantageous over the more efficient solvent extraction equipment. Furthermore, materials pressed out generally have better preserved native properties, end products are free of chemicals and it is a safer process. However, extraction by just pressing the seeds is relatively inefficient. It is advisable to research new methodologies for pretreating substrates that also allow for better retention and availability of desirable plant metabolites. Within these pretreatments, the radiation microwave is included. There is not much information in the literature about the application of microwave radiation as a pretreatment for Chilean hazelnut and its effect on the microstructure of the substrate, extraction yield and quality of oil. The aim of the present study was to investigate the impact of pretreatment by microwave radiation prior to the oil extraction by pressing on the microstructure, recovery of oils and oil quality of Chilean hazelnut seeds (G. avellana Mol).     

Enzymatic treatment to improve the quality of black tea extracts

Enzymatic extraction was investigated to improve the quality of black tea extracts with pretreatment of pectinase and tannase independently, successively and simultaneously. Pectinase improved the extractable-solids-yield (ESY) up to 11.5%, without much of an improvement in polyphenols recovery, while tannase pre-treatment showed a significant improvement in polyphenols recovery (14.3%) along with an 11.1% improvement in ESY. Among the four treatments, tannase-alone treatment showed the maximum improvement in tea quality, with higher polyphenols-in-extracted solids. Treatments involving tannase resulted in the significant release of gallic acid, due to its hydrolytic activity, leading to greater solubility besides favourably improving TF/TR ratio. The results suggested that employing a single enzyme, tannase, for the pre-treatment of black tea is desirable. Enzymatic extraction may be preferred over enzymatic clarification as it not only displayed reduction in tea cream and turbidity but also improved the recovery of polyphenols and ESY in the extract, as well as maintaining a good balance of tea quality.     

立地对油茶籽出油率及油茶籽油品质的影响研究

为了探明立地对油茶籽出油率及油茶籽油品质的影响,以9个立地的低温压榨油茶籽油为样品,测定油茶籽出油率及油茶籽油的理化性质、感官品质、脂肪酸组成、功能性成分含量及氧化诱导时间,分析坡向、坡位因子对油茶籽出油率及油茶籽油品质的影响。结果表明:立地对油茶籽出油率及油茶籽油的过氧化值、碘值、皂化值、感官品质、功能性成分含量及氧化诱导时间均具有明显影响,对油茶籽油的酸价、脂肪酸组成无明显影响。说明立地是影响油茶籽出油率及油茶籽油品质的重要因素。     

高压脉冲电场处理对初榨橄榄油得率和品质的影响

为开发一种能提高初榨橄榄油(VOO)得率、对品质无不利影响且适用于工业化生产的新工艺,以甘肃陇南产区莱星、鄂植8号品种油橄榄鲜果为原料,采用高压脉冲电场(PEF)处理辅助传统工艺提取VOO,通过与传统提取工艺比较,研究PEF处理对VOO得率、理化性质、总多酚含量和脂肪酸组成及相对含量的影响。结果表明:与传统提取工艺相比,采用PEF处理VOO得率平均增幅为15.38%,果渣含油率平均降幅为22.28%,对VOO的色泽、酸值、过氧化值、总多酚含量和脂肪酸组成及相对含量等总体无显著性影响。研究认为,在VOO传统提取工艺的基础上,鲜果破碎之后增加PEF处理环节,可显著提高VOO得率,而且对VOO品质无不利影响,该技术在VOO工业化生产中有良好的应用潜力。     

Papaya: Nutritional and pharmacological characterization, and quality loss due to physiological disorders. An overview

The papaya (Carica papaya L.) is a tropical fruit that is widely cultivated and consumed, both for its agreeable flavor as well as its many pharmacological properties. This review will discuss the fruit's origin and principal growing regions in the world and will briefly explore its nutritional and pharmacological attributes. In addition, we will identify and comment on some of the most common physiological disorders that occur postharvest. Such disorders compromise the quality of the fruit, bringing financial losses to the productive sector, along with serious economic and social consequences to papaya-growing countries. Among these disorders, physiological bruising, also known as “skin freckles”, characterized by the appearance of blemishes on the fruit while still in its growth stage, is one of the main problems associated with the crop. Possible causes of and current information on bruising are dealt with in this article. Other physiological disorders of the papaya such as pulp flesh translucency, pulp softening, and hard lumps in papaya flesh are also discussed.     

发酵豆奶的生产工艺和营养

<正> 大豆是我国的传统食品,蛋白质含量达45％左右,为一般食物含量的3～5倍。现代营养学认为,蛋白质的营养价值主要取决于其氨基酸成分,如果各种氨基酸比例接近人体的氨基酸模式,即符合FAO/WHO建议的氨基酸模式,则该种食物的营养价值高。大豆中蛋白质的必需氨基酸模式不但接近FAO/WHO的建议模式,也与动物蛋白质的氨基酸模式相近,是一种完整的蛋白质。另一方面,大豆蛋白质与奶类或谷类食物搭配,具有蛋白质互补的作用。而且大豆中的脂肪含量达     

如何提高甜菜种子产量及发芽率

文章阐述了提高甜菜种子产量及发芽率需要注意的选根、栽培措施、辅助授粉、收获、加工、贮藏及去除种皮有害物质等问题,并提出了解决问题的几点看法.     

微波预处理对奇亚籽出油率及油脂品质的影响

采用微波技术对奇亚籽进行预处理后低温压榨制油,测定奇亚籽油理化指标、营养及抗氧化指标,探讨微波预处理条件对奇亚籽出油率以及奇亚籽油品质的影响。结果表明：原料的水分含量、微波时间、微波功率对奇亚籽出油率和奇亚籽油的理化指标、黄酮含量、多酚含量及DPPH·和O-2·清除能力均有一定的影响,对奇亚籽油脂肪酸相对含量影响较小。经单因素实验和正交实验得出：微波预处理奇亚籽的适宜工艺条件为奇亚籽水分含量12%、微波时间3 min、微波功率600 W,在该条件下奇亚籽出油率可达到21.05%,奇亚籽油酸价（KOH）0.52 mg/g、过氧化值0.44 mmol/kg、黄酮含量318.25 mg/kg、多酚含量28.00 mg/kg,DPPH·和O-2·清除率分别为2479%和26.84%。     

Functional food ingredient quality: Opportunities to improve public health by compendial standardization

Functional food ingredients often include well-characterized dietary supplement ingredients, and are expected to deliver corroborated structure/function declarations and may support health claims. A compendial monograph for a functional food ingredient, as exemplified in the Food Chemicals Codex (FCC), is vetted and made official by elected volunteer experts in the Food Ingredients Expert Committee of the Council of Experts of the United States Pharmacopeial Convention (USP). As a result, manufacturers and other stakeholders can use these public standards to conduct tests that assure the quality of functional foods and food ingredients in commerce. FCC monographs complement adherence to current good manufacturing practices for foods and dietary supplements, and provide minimum quality standards during safety and exposure evaluation.     

Meat quality evaluation by hyperspectral imaging technique: an overview

During the last two decades, a number of methods have been developed to objectively measure meat quality attributes. Hyperspectral imaging technique as one of these methods has been regarded as a smart and promising analytical tool for analyses conducted in research and industries. Recently there has been a renewed interest in using hyperspectral imaging in quality evaluation of different food products. The main inducement for developing the hyperspectral imaging system is to integrate both spectroscopy and imaging techniques in one system to make direct identification of different components and their spatial distribution in the tested product. By combining spatial and spectral details together, hyperspectral imaging has proved to be a promising technology for objective meat quality evaluation. The literature presented in this paper clearly reveals that hyperspectral imaging approaches have a huge potential for gaining rapid information about the chemical structure and related physical properties of all types of meat. In addition to its ability for effectively quantifying and characterizing quality attributes of some important visual features of meat such as color, quality grade, marbling, maturity, and texture, it is able to measure multiple chemical constituents simultaneously without monotonous sample preparation. Although this technology has not yet been sufficiently exploited in meat process and quality assessment, its potential is promising. Developing a quality evaluation system based on hyperspectral imaging technology to assess the meat quality parameters and to ensure its authentication would bring economical benefits to the meat industry by increasing consumer confidence in the quality of the meat products. This paper provides a detailed overview of the recently developed approaches and latest research efforts exerted in hyperspectral imaging technology developed for evaluating the quality of different meat products and the possibility of its widespread deployment.     

Quantifying and predicting meat and meat products quality attributes using electromagnetic waves: An overview

The meat industry needs reliable meat quality information throughout the production process in order to guarantee high-quality meat products for consumers. Besides laboratory researches, food scientists often try to adapt their tools to industrial conditions and easy handling devices useable on-line and in slaughterhouses already exist. This paper overviews the recently developed approaches and latest research efforts related to assessing the quality of different meat products by electromagnetic waves and examines the potential for their deployment. The main meat quality traits that can be assessed using electromagnetic waves are sensory characteristics, chemical composition, physicochemical properties, health-protecting properties, nutritional characteristics and safety. A wide range of techniques, from low frequency, high frequency impedance measurement, microwaves, NMR, IR and UV light, to X-ray interaction, involves a wide range of physical interactions between the electromagnetic wave and the sample. Some of these techniques are now in a period of transition between experimental and applied utilization and several sensors and instruments are reviewed.     

超声波辅助提取对亚麻籽油得率和品质的影响

以亚麻籽为原料,利用超声波辅助提取技术提取亚麻籽油,研究超声波辅助提取工艺参数对亚麻籽油提取得率和品质的影响。结果表明:虽然较高的提取温度、超声波功率和较长的提取时间在一定程度上利于亚麻籽油提取得率的增加,但是却会导致亚麻籽油品质下降(酸值、过氧化值升高,碘值降低)。综合考虑亚麻籽油的提取得率和品质,各因素对亚麻籽油生产影响的主次顺序为:超声波功率提取温度提取时间。根据正交试验,超声波辅助提取亚麻籽油的最优工艺参数为:提取时间25 min,提取温度35℃,超声波功率800 W。     

Evaluation of size reduction on the yield and quality of celery seed oil

The effect of grinding/flaking with and without pre-cooling of celery seeds on the yield and physical and chemical characteristics of volatile oil was evaluated. For smaller batches (200 g) with pre chilling and flaking, yields of oil were marginally but consistently higher (2.20%), compared to grinding celery at ambient temperature using a mini plate mill (1.9%) and with waring blender (1.8%). With flaking at room temperature the yield of oil was 2.0%. However, in large batches (10 kg), with steam distillation the yield of steam distilled oil was significantly higher for flaking (1.76%) as compared to the hammer mill powdering (1.4%), both at room temperature. Extraction of volatile oil from celery powder or flakes follows first order kinetics with an variance value of 0.04. Gas chromatograph (GC) and gas chromatograph–mass spectra (MS) analysis showed that in case of flaking, the volatile oil had higher levels of limonene, the major volatile compound and sedanenolide, the major character impact compound being present in almost equal quantities in both the cases of flakes and powder. Selective collection of volatile oil at different intervals of time of distillation gave products of different flavour profiles. Flaking had the advantage of higher yields of the volatile oil with better flavour quality. It was also observed that flaking of celery helped in overcoming the problem of clogging and choking which is associated with the conventional grinding.