Some flavouring constituents of fermented fish sauces

The aroma of fermented fish sauce comprises three distinct notes, cheesy, meaty and ammoniacal. Analysis showed that the cheesy odour was produced by lower fatty acids and the ammoniacal odour by ammonia and amines. The meatyaroma was much more complicated and was not analysed, but it was shown that it could be produced by atmospheric oxidation of precursors that were still present in mature sauces. Individual fatty acids were determined in sauces at various stages of fermentation and an hypothesis explaining the origin of the acids is deduced from the results.     

调香及其在饮料产品中的作用

对香精的制造,种类,应用及质量加以介绍,着重论述了调查在饮料产品中的主要作用。     

A study of the volatile flavouring constituents of canned Malayan pineapple

About 35 volatile compounds have been detected in canned Malayan pineapple and 18 of these have been identified by the gas chromatographic analysis of headspace vapours using columns containing polyethylene glycol 400, di-(2-cyanoethyl) ether and polypropylene glycol. A new method of sampling headspace vapours is described. Peaks in the chromatograms were classified by subtraction with group reagents, namely dimedone, hydroxyammonium chloride and alkaline hydroxyammonium chloride, which removed aldehydes, all carbonyl compounds, and esters and carbonyl compounds respectively. Individual compounds were identified by their relative retentions on three different stationary phases.     

Improved enzymic assay for cyanogens in fresh and processed cassava

The assay for cassava cyanogens developed at the Natural Resources Institute has been modified to overcome some of the problems encountered when the assay is applied to cassava products. Inclusion of 25% ethanol in the extraction medium increased the volume of recovered extract from heat-processed cassava products, eliminated the need for centrifugation and did not interfere with any aspect of the assay. Greater cyanohydrin recovery was noted and the calculation for cyanogen contents was changed to take into account the total extract volume. The separate assay of the three cyanogens (glucosides, cyanohydrins and free cyanide) was achieved by buffering aliquots of the extract followed by appropriate treatment. The importance of assaying for free cyanide (HCN) at pH 4 was demonstrated. Above this pH, cyanohydrin degradation also produces free cyanide, giving rise to misleading values. The efficiency of the extraction medium in recovering added linamarin and cyanohydrin from cassava foods was determined. Recoveries of cyanohydrin were improved using the ethanol/acid medium. The stability of the cyanogens in the ethanol/acid extraction medium was tested at ambient and refrigeration temperatures. Over a two-month period, refrigerated extracts showed acceptable variation as compared with normal variation within the assay (5%) for total and non-glycosidic cyanogens but the levels of free cyanide showed heavy losses (15–56% lost). Since the relative toxicities of the three cyanogens have yet to be ascertained, the relative amount of each cyanogen may be important when assessing the safety of cassava products.     

Comparative study on nutrient and anti‐nutrient changes in Ikivunde and Inyange,two Burundian traditionally processed cassava products

A comparative study on nutrients and anti‐nutrients in Ikivunde and Inyange and a correlation of nutrients and anti‐nutrients with fermentation time during processing of both products were carried out. In Ikivunde, all nutrients and anti‐nutrients had high negative correlations with fermentation time, except for crude fibre, fats and calcium, which showed high positive correlations. In Inyange, all nutrients and anti‐nutrients were positively correlated with fermentation time, except for starch, ash, zinc, magnesium, calcium, glutamine and alanine. Analysis of variance showed that Ikivunde and Inyange differed significantly (P < 0.05) in reducing sugar, protein, ash, cyanide, phytic acid and tannin contents at various fermentation times. There were also significant differences (P < 0.05) between Ikivunde and Inyange in starch and fat contents at 48, 72, 96 and 120 h, while for crude fibre a significant difference was observed from 72 h until the end of fermentation. At the end of the fermentation period (120 h), Inyange had higher starch, protein, amino acid, reducing sugar, ash, iron, zinc, potassium, sodium, magnesium, fat, cyanide, phytic acid and tannin contents but lower crude fibre and calcium contents than Ikivunde. The results from this study showed that Inyange contains more nutrients and anti‐nutrients than Ikivunde. Copyright © 2006 Society of Chemical Industry     

Thermophysical properties of processed meat and poultry products

Thermophysical properties of various meat and poultry emulsions were evaluated at four temperatures (20, 40, 60 and 80 °C). Thermal conductivities (0.26–0.48 W m⁻¹ K⁻¹) increased linearly with temperature between 20 and 60 °C. Between 60 and 80 °C, it remained constant for most products except bologna. Curves for thermal conductivity as a function of temperature could be roughly grouped into two different categories: products containing meat particles and those containing meat emulsions. The application of various models was investigated for thermal conductivity prediction. It was found that a three phase structural based Kirscher model had the potential for predicting thermal conductivities with acceptable accuracy. Densities decreased slightly as a function of temperature from 20 to 40 °C. A transition phase was observed from 40 to 60 °C, which was followed by a decrease from 60 to 80 °C. There was a decrease of about 50 kg m⁻³ between the density of a raw product at room temperature (at maximum 1070 kg m⁻³) and the product heated to 80 °C (at minimum 970 kg m⁻³), due to the gelation or setting of the structure. After a transition period from 10 to 30 °C, the heat capacity increased linearly from 30 to 80 °C, and ranged from 2850 to 3380 J kg⁻¹ °C⁻¹, respectively. Densities and heat capacities were strongly influenced by the carbohydrate content (i.e. as the carbohydrate content increased the density decreased). The salt content adversely affected thermal conductivity and thermal diffusivity values. However, these parameters increased with moisture content.     

Antioxidant properties of differently processed spinach products

The effect of variously processed spinach products (whole-leaf, minced and enzymatically liquefied spinach) on lipid oxidation was determined. In an autoxidative methyl linoleate (MeLo) system the inhibition of hydroperoxide formation, measured by HPLC after three days of oxidation, was in descending order: whole-leaf > liquefied > minced spinach. The inhibition of formation of thiobarbituric acid-reactive substances (TBARS) and hexanal by spinach was determined in cooked meatballs with added spinach after two days of storage at 4 degrees C. The formation of TBARS was inhibited by liquefied spinach at 200 g/kg meat; all other spinach products tested at 100 and 200 g/kg were pro-oxidative. The formation of hexanal was inhibited by both minced and liquefied spinach at 100 and 200 g/kg meat. The variously processed spinach products behaved differently when tested for their antioxidant activity (MeLo) or oxidative stability (meatballs). We conclude that the effect of spinach products on lipid oxidation is affected by processing.     

青稞加工制品研究进展

青稞是高原特色作物,由于青稞特殊的生长地域及营养成分,其加工制品的相关研究成为热点。从青稞软饮料、青稞发酵制品、青稞粮谷制品等领域,综述了青稞加工制品的最新研究进展,分析了我国青稞制品及其加工行业存在的问题,对青稞加工未来发展方向做出了展望。     

乳及乳制品加工中的美拉德反应

针对乳及乳制品在加工和储藏过程中由于发生美拉德反应不仅使乳制品的营养物质受到破坏，还产生对人体有害的物质，在很大程度上影响的乳制品的质量，对乳制品中美拉德反应的历程，产生的标志物及其测定方法等进行了的综述。     

面食的品质和食品添加剂

面食是我国13亿人口一日三餐主食的主要品种，特别是在北方地区。2000年我国城乡消费小麦1.1亿多吨。一、不同面食的品质要求随着经济的发展，生活节奏的加快，作为主食的面食品，其品种和数量将不断增加，这是一种必然趋势，提高面食品的质量也是客观的要求。但是我国小麦的筋力较差，较难适应制作高质量面食的多种要求。为了满足各种面食品对面粉质量的多种要求，国家粮食部门研究开发了9种食品专用粉标准，并经国家技术监督局批准实施。9种专用粉是：面包用小麦粉、面条用小麦粉、饺子用小麦粉、馒头用小麦粉、发酵饼干用小麦粉、苏性饼…     

Microbiological aspects and shelf life of processed seafood products

BACKGROUND: Fresh fish and seafoods are very perishable products mainly owing to microbial activity of specific spoilage micro‐organisms. Application of hurdle technology leads to a variety of processed products with extended shelf life. In this study, sensory evaluation and microbiological analysis were carried out on 17 processed seafood products stored at 4 °C to determine their shelf life and the predominant spoilage micro‐organisms. RESULTS: Shelf life determined by sensory analysis varied from 66 to 180 days depending on the product. The cause of spoilage for most of the products was the development of off‐flavours/off‐odours, while two products were rejected owing to oil discolouration. Pseudomonads were in most cases below detection limit. H₂S‐producing bacteria, Brochothrix thermosphacta and Enterobacteriaceae were below detection limit throughout the experiment. The predominant spoilage micro‐organisms were lactic acid bacteria and yeasts. Hygiene indicators such as Staphylococcus spp. and total coliforms were also below detection limit in all samples. CONCLUSION: Primarily the initial pH and secondarily the NaCl content determined shelf life duration. Under the applied conditions, lactic acid bacteria and yeasts predominated. The contribution of chemical oxidation and/or autolysis to spoilage and shelf life might be important for most of the products. © 2012 Society of Chemical Industry     

Cyanogenic potential of randomly sampled fresh and processed cassava on retail sale in Singapore

A random sample of fresh cassava roots and cassava products, purchased at various retail outlets in Singapore during 2016–2017, had total cyanogenic potential (CNp–expressed as mean ± standard deviation, mg kg⁻¹ HCN, fresh weight basis) as follows: fresh roots (n = 66) from three SE Asian countries, 59.0 ± 19.2; peeled chilled root pieces from Malaysia (20 × 1-kg packs), 38.5 ± 16.5; cassava flour from Indonesia (8 × 1-kg packs), 11.7 ± 8.2; dried Indonesian chips for home frying (5 × 250 g packs), 61.6 ± 16.5; one pack (120 g) of Malaysian ready-to-eat (RTE) chips, 17.1 ± 3.2. CNp in all flour and RTE chips was below 20 mg kg⁻¹. The majority of fresh roots (59.1%) and packs of dried chips (80%), and 15% of packs of peeled chilled root parenchyma, exceeded the Codex Alimentarius limit (50 mg kg⁻¹) for ‘sweet’ (boil-and-eat) cassava.     

调味品与调味的关系

调味品是根据普通人的口味需要 ,添加在食物中的增香、增色、增味或去弃异味的调味原料、调料。调味品种繁多 ,有天然的 ,也有人工制造的 ;有动植物性产品 ,也有矿物性产品 ;有鲜品 ,也有干品 ;有液态、油态、粉状、糊状、膏状等。按商品分类为酿造类、腌渍类、鲜菜类、干品类、水产类及其他类。调味品的繁多 ,与地区有关 ,与风土人情有关 ,虽然人对食物味的感觉十分复杂 ,可因食物的种类不同 ,成分不同 ,调味不同 ,而感觉自然不一样了。人们对味的感觉大致有三种 :(1 )物理味觉 :是指人们对食物的软硬度、粘度、冷热度、咀嚼感、口感、触感…     

酶制剂在番茄制品加工中的应用

果胶酯酶NovoShape在番茄制品加工中的应用明显提高了番茄丁、去皮整番茄的成型率,并赋予成品饱满、光滑的外观,同时又很好地保持了番茄原有的良好风味和色泽,从而提高了番茄制品的品质。      

Antioxidant properties of polyphenol-rich cocoa products industrially processed

Fermentation and roasting are the main causes of polyphenol degradation during the process for obtaining cocoa products. In the present study, a process for obtaining polyphenol-rich cocoa products on an industrial scale is described. The process avoids the fermentation and roasting steps and includes a step for the inactivation of the enzyme Polyphenol Oxidase (PPO), which helps preserve the polyphenol content present in the raw cocoa bean. In addition, our study evaluates the antioxidant capacity and characterizes the flavonoid profile of the polyphenol-rich cocoa products obtained from the natural polyphenol-rich cocoa cake. Using different protocols, we have obtained three cocoa extracts with high polyphenol content, namely extracts A (167 mg/g), B (374 mg/g) and C (787 mg/g). The scavenging capacity of the extracts was measured as their ability to bleach the stable radicals DPPH and ABTS⁺ while their antioxidant effect was evaluated with the FRAP assay. The results for A, B and C in the DPPH test expressed as Trolox equivalent (μmol)/mg dry weight of extract were 0.2, 1.4 and 3.0, respectively; in the ABTS test the results were 1.0, 4.7 and 9.8. The antioxidant capacity expressed as ascorbic acid equivalent (μmol)/mg dry weight of each product were 17.2, 76.1 and 207.7, respectively. The scavenging properties of cocoa powder against the superoxide anion, H₂O₂, HClO, and peroxynitrite were also determined. The IC₅₀ (μg/mL) values in the hypoxanthine/xanthine oxidase test were 77.5, 12.3 and 10.3, for A, B and C, respectively, while as an HOCl scavenger the IC₅₀ (μg/mL) values were 225.4, 73.2 and 21.5. As a peroxynitrite anion scavenger, only extract C had a relevant effect, with IC₅₀ (μg/mL) values of 76.1 or 110.0 in the absence or presence of bicarbonate. None of the extracts tested showed activity in the hydrogen peroxide test, but B and C significantly increased the deoxyribose degradation in the absence of ascorbate. Likewise, none of the extracts inhibited the ferrous or copper chelating activity at 100 μg/mL, but they inhibited the lipid peroxidation in brain homogenates and human plasma through non-enzymatic generation systems, with extract C giving the best IC₅₀ (μg/mL) values: 17.4 and 8.1 against lipid peroxidation in brain homogenates and human plasma, respectively. In conclusion, if the extractive protocol is well characterized, defined and optimized, cocoa could constitute a source of polyphenols for enriching foods, nutraceuticals and alimentary supplements.     

Detection of allergenic additives in processed meat products

Allergic responses to food components are an increasing problem all over the world. It is therefore important to protect people who are vulnerable to food allergens against accidental and unintended consumption of products containing allergic ingredients. The meat industry commonly uses various allergic additives in the production of processed products, such as legumes (soy, peas, beans), milk and egg preparations, cereals containing gluten (wheat, rye, barley and oats), and spices (celery and mustard). These meat additives have specific technological properties, which help to create a texture or flavor profile, or affect the nutritional value, although some of them, such as soy, mustard, milk and egg white proteins, can cause severe allergic reactions. The aim of this paper is to discuss the application of various recently established methods of detection of allergenic additives in processed meat products – for instance cold cuts and sausages. The new methods are based mainly on protein, DNA, and isoflavones or phytic acid analysis. The article also characterizes the latest trends in the development of research on methods that would enable quick and reliable identification of targeted allergens in meat products. © 2018 Society of Chemical Industry     

辐照技术在猪肉加工制品中的应用

详细阐述了辐照技术对猪肉加工制品的感官和成品中的蛋白质、脂肪和碳水化合物等成分的影响.并对辐照技术在猪肉加工制品中,延长保存期和安全性等关键作用方面做了论述.用10kGy以下辐照剂量处理过的食品,其风味、色泽,内部的蛋白质、脂肪和维生素等基本保持稳定,同时可以有效地延长猪肉加工制品的保存期.     

Picrate paper kits for determination of total cyanogens in cassava roots and all forms of cyanogens in cassava products

The simple semiquantitative picrate method for the determination of total cyanogens in cassava flour has been modified by increasing the concentration of the picrate solution used to make up the picrate papers, such that a linear Beer's Law relation between absorbance and cyanogen content is obtained over the range 0–800 mg HCN equivalents kg⁻¹ cassava. The method has been adapted to determine the total cyanogen content of cassava roots and the results compared using the picrate method and the acid hydrolysis method for six different roots from five cultivars. The agreement between the results is satisfactory. The simple method for determination of total cyanogens in cassava roots in the field is available in kit form. The methodology has been modified to allow determination of the three different forms of cyanogens present in cassava flour, viz HCN/CN⁻, acetone cyanohydrin and linamarin. HCN/CN⁻ is determined by the picrate method in which cassava flour is reacted with 0.1 M sulphuric acid for 3 h at room temperature. HCN/CN⁻ plus acetone cyanohydrin is also determined by the picrate method after treating cassava flour with 4.2 M guanidine hydrochloride at pH 8 for 3 h at room temperature. A comparison has been made of the amounts of the three cyanogens present in six cassava flour samples using the semiquantitative picrate and the acid hydrolysis methods. The agreement between the two methods is satisfactory, which shows that the new methodology works well. The picrate method for determination of the three cyanogens in cassava flour is also available as a kit. © 1999 Society of Chemical Industry