Cassava as a non-conventional filler in comminuted meat products

Cassava (Manihot esculenta) was used as an unconventional filler to produce affordable comminuted meat products that stored well under tropical conditions without refrigeration. The study involved two experiments. In experiment 1, five different emulsion-type pork sausages containing 5.4, 9.0 and 10.0% mould-free cassava flour, 5.4% crude full fat soy flour and a control without filler were assessed 0 and 7 days after preparation. A 40-member taste panel sensorily assessed the products in a 5 × 2 factorial (treatment × storage occasion) experiment based on the external appearance of the uncooked products and the external and internal colour, consistency, texture, aroma and taste of the cooked products. Although the panel judged products with 5.4% cassava flour as the best, the 9% inclusion level of cassava flour was found not to compromise the organoleptic qualities of the product. At this level 54 000 cedis (US$150) was saved on the cost of producing 1t of the product. In experiment 2, the sausages were pasteurised at 80 °C for 1 h and stored in a 4:1 vinegar-sugar solution or a 1:1:50 vinegar-sugar-water solution at 5 and 30 °C. Storage in 4:1 vinegar-sugar medium arrested bacterial growth over the 7-day monitoring period. It was concluded that 9% cassava flour could conveniently replace fat in comminuted meat products and a combination of pasteurisation and storage in vinegar-sugar solution is an effective method of storage of such products in the tropics.     

Lactulose as a food ingredient

Lactulose is a synthetic ketose disaccharide that can be obtained from lactose by different methods of synthesis. Chemical methods are based on the isomerization of lactose in the presence of basic catalysts and enzymatic methods using lactose as a galactose donor and fructose as an acceptor. The prebiotic properties of lactulose have been known for more than 50 years and numerous studies have confirmed several health benefits of lactulose as a food ingredient, including selective stimulation of intestinal flora, laxative effect and improvement of calcium absorption. Its use in fermented milk manufacture may reduce the incubation period and favour the growth of bifidobacteria. The synthesis of lactulose‐derived oligosaccharides may provide a new group of prebiotics with properties complementary to those of native lactulose. Copyright © 2009 Society of Chemical Industry     

Lime characterization as a food additive

This article discusses the use of various measurement techniques for physico-chemical and mineralogical analyze of lime for its safe use as a food additive. Two types of samples were taken from a mine in Queretaro, Mexico, and measurements were made to determine Pb (CaO—0.0012 mg/kg, Ca(OH)₂—0.0527 mg/kg), As (CaO—0.0290 mg/kg, Ca(OH)₂—0.0849 mg/kg), F (under the quantification limit), and V (CaO—1.9068 mg/kg, Ca(OH)₂—4.3403 mg/kg). The samples were within the safety limits for human consumption. It is suggested that similar analysis be carried out on commercially marketed lime products.     

Ice-cream as a probiotic food carrier

Ice-creams are food products showing potential for use as probiotic vehicles, with the added advantage of being appreciated by people belonging to all age groups and social levels. However, the development of ice-creams containing probiotic bacteria requires the overcoming of certain technological intrinsic requirements related to their processing stages. The aim of the present paper was to review the technological parameters involved in the production of probiotic ice-creams. Although the application of probiotics in cheeses, and especially in fermented milks, has been widely explored in the literature, ice-cream is a relatively innovative matrix for the application of probiotics, and thus a review about its potential as probiotic food carrier could be very helpful.     

PVC as a food packaging material

Manufacture of polyvinyl chloride (PVC) in western Europe for all applications is now almost 4 m tonnes and the UK accounts for about 400 kt of this.The aim of this paper is to illustrate the relative importance of PVC as a packaging material where, in the UK for example, for food packaging it accounts for almost 40 kt (10%) of the PVC used.The different types of PVC packaging material—bottles, foil, cling film and cap sealing—and their method of manufacture are described, together with the range of food packaging applications in which they are used. The physical properties of PVC are described and, additionally, its cost and competitiveness with other materials are compared. The chemical nature of PVC compositions arising from the addition of heat stabilisers and plasticisers to achieve the desired properties is also described, with particular reference to heat stability.With the VCM toxicity issue now behind us, and PVC polymer with a maximum level of 1 ppm vinyl chloride monomer (VCM) being supplied for food packaging, PVC must be the most stringently controlled and thoroughly researched material for food packaging. Recent developments in polymerisation technology and polymer manufacture, which have enabled this level to be achieved, are briefly described.The current situation on the global migration issue, on which attention is currently focused, not only for plasticised PVC, but also other packaging materials as well, is briefly reviewed.     

An Evaluation of Cassava Starch as a Gelling Material for Electrochemical Salt Bridges

Cassava starch was investigated for its potential use as a gelling material for electrochemical salt bridges. Different electrolytes, KCl, NH₄ and NH₄NO₃, were mixed with the starch and the resulting voltage of a Zn–Cu Cell in which it is used as a salt bridge was measured. The observed voltage agreed with the theoretical voltage within 3.6% error. It was observed that the starch and ammonium nitrate electrolyte produced a better blend, gave more reproducible values and has the lowest resistance of all the other electrolyte-starch mixtures.     

Twin-Screw Extrusion as a Continuous Pretreatment Process for the Enzymatic Hydrolysis of Cassava

Twin-screw extrusion was evaluated as a pretreatment for the enzymatic hydrolysis of cassava starch to glucose. Extrusion temperature and pH affected the key parameters associated with the enzymatic hydrolysis of starch such as the water solubility index, the water absorption index, the apparent viscosity, and the susceptibility of the extruded starch to glucoamylase. The glucose concentration of extruded and enzyme-hydrolyzed cassava starch was approximately 5% greater than that of acid-liquefied and enzyme-hydrolyzed cassava starch.     

Cassava leaf meal as a replacement for coconut oil meal in pig diet

Two feeding trials were conducted to evaluate cassava leaf meal (CLM) as a replacement for coconut oil meal (COM) in tropical pig diets. In each trial, 36 pigs (initial weight, 14.5 kg) were limit fed diets containing 0, 133, 267 and 400 g kg^?1 CLM substituted for equal amounts (w/w) of COM in a 179 g kg^?1 protein basal diet. An extra-period Latin-square changeover design with 2-week periods was used. Average daily gain and feed efficiency were improved when diets containing 133 g kg^?1 CLM were fed, which may be attributed to the higher lysine content of CLM. Daily gain and feed efficiency of pigs fed diets containing 267 g kg^?1 CLM were similar to those on the basal diet. Poor performance of pigs fed the 400 g kg^?1 CLM diets may be explained by the low energy content and the presence of anti-nutritional factors, such as cyanide and tannin, in CLM. Two balance trials were conducted using 16 barrows (castrated male pigs, initial weight, 37.2 kg). Apparent digestibility coefficients for dry matter, energy, protein, cell contents, cell wall and hemicellulose were depressed, whereas those for ash and lignin were improved as CLM was substituted for COM. The data indicate that cassava leaf protein is utilised efficiently, although other nutrients in CLM are not as digestible as those in COM.     

Color as a factor in food choice

From birth, nature teaches us to make judgements on our environment based in large measure on color. As such, it plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Its role is elusive and difficult to quantify, however, which at times has placed color in a secondary role to the other sensory characteristics, a position not entirely consistent with the facts. Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods. Studies in the literature have used cross‐sectional population panels to study these effects, but a recent investigation of color‐sensory interactions in beverages has compared the response of a college age group with the response of a panel consisting of a more mature population. Interestingly, the older group showed significant differences from the college age group in their response to the effects of color on several sensory parameters as well as showing a direct correlation between beverage consumption and color. Color is often taken for granted, but this position must be reevaluated in view of such studies and the need to create more appealing foods for different segments of our society.     

Cassava leaves as animal feed: Potential and limitations

The nutrient composition and potential productivity of cassava (Manihot esculenta Crantz) leaves are examined, and their usefulness as a protein supplement in animal nutrition in the tropics is reviewed. On average, meal prepared from cassava leaves contains (on a dry matter basis) 210 g kg^?1 crude protein, 250 g kg^?1 acid detergent fibre, 85 g kg^?1 ash, 14.5 g kg^?1 calcium and 4.5 g kg^?1 phosphorus. Cassava leaf protein is well balanced, except for a deficiency of sulphur-containing amino acids. The presence of hydrocyanic acid and tannins is considered, but a leaf meal with low levels of these anti-nutritional factors may be prepared using simple processing techniques. The most immediate prospects for the use of cassava leaf products are in the following areas: (i) low level inclusion of leaf meal in feed formulations for monogastric animals, and (ii) fresh forage as a protein supplement to low-quality roughages in ruminant feeding. Relevant future research needs are also identified.     

Starch as a functional component of food systems

Starch and other carbohydrates of D-glucose series bind sodium ions but don't bind calcium ones. The affinity of beta-glucosides to sodium ions is much stronger than the affinity of D-glucose and of alpha-glucosides. Some other interrelations between the components of starch-containing food systems are briefly discussed.     

Instant food products as a source of silicon

Silicon is a trace element for humans, and is absorbed from food in the form of orthosilicic acid. Instant food products are part of a constantly growing market of convenience foods, which have not been evaluated yet as sources of silicon. In this study the total and soluble silicon contents in different instant food products were determined by using graphite furnace atomic absorption spectrometry (GF-AAS). A selection of instant products commercially available in Wroclaw were analyzed: soups, main courses, coffee drinks, jellies and puddings. Total silicon contents in soups, main courses and coffee drinks ranged widely and reached the values: 0.10–30.20, 0.63–37.91 and 0.21–13.37 mg/serving, respectively. These products contained 0.05–1.26 mg of soluble silicon per serving. The total silicon content in jellies and puddings did not exceed 0.36 mg and 2.42 mg/serving, respectively. Among the analyzed desserts the highest level of soluble silicon was found in chocolate puddings: 0.36–0.41 mg/serving. The silicon level in servings of the studied instant products when prepared with the appropriate amount of water was also estimated. The mean content of silicon determined in samples of drinking water from Wroc?aw and the vicinity, which was used for the estimation, amounted to 7.09 mg/l. The total silicon content in ready-to-eat products ranged from 1.32 to 39.21 mg/serving. In conclusion, some of the analyzed instant foods contained very high amounts of silicon, however the content of the soluble, and hence available, form of this element was low.     

Processing Techniques to Reduce Toxicity and Antinutrients of Cassava for Use as a Staple Food

ABSTRACT: Cassava is a valuable source of food for developing countries, but it contains highly toxic cyanogen compounds and antinutrients. Cyanogens are found in 3 forms in cassava: cyanogenic glucoside (95% linamarin and 5% lotaustratin), cyanohydrins, and free cyanide. Different processing techniques exist to remove cyanogens and their effectiveness depends on the processing steps and the sequence utilized, and it often is time‐dependent. Pounding or crushing is the most effective for cyanogenic glucoside removal because it ruptures cell compartments, thus allowing direct contact between linamarin and the enzyme linamarase that catalyzes the hydrolytic breakdown. Crushing and sun‐drying cassava roots made into flour removes 96% to 99% of total cyanogens, whereas soaking and sun‐drying into lafun or fufu, or soaking and fermenting and roasting into gari or farina, removes about 98% of cyanogens. For cassava leaves, which have 10 times more cyanogens than roots, pounding and boiling in water is an efficient process to remove about 99% of cyanogens. Other strategies to reduce toxicity include development of low‐cyanogen cassava varieties and cassava transgenic lines with accelerated cyanogenesis during processing. Although phytate and polyphenols have antioxidant properties, they interfere with digestion and uptake of nutrients. Fermentation and oven‐drying are efficient processing methods to remove phytate (85.6%) and polyphenols (52%), respectively, from cassava roots. Sun‐drying the leaves, with or without prior steaming or shredding, removes about 60% phytate. Cassava is a nutritionally strategic famine crop for developing countries and, therefore, reducing its toxicity and improving its nutritional value is crucial.     

木薯原料生产酒精的关键技术

木薯原料生产酒精的关键技术 :(1)适当减小引风机风量 ,避免粉尘飞扬 ,减少淀粉损失 ;(2)预煮拌料水温控制在55±5℃ ,蒸煮温度135±5℃ ,糊化时间80min以上 ,糖化温度58～60℃ ;(3)用酶量140～150u/g料 ,糖化时间40～50min;(4)干酵母采用小酒母和大酒母两级培养 ,芽生率稳定在18 %～25 % ,细胞数0.9～1.5亿/ml;(5)发酵顶温35～37℃ ,48～56h发酵结束。成品酒精质量达到国标普级标准 ,原料出酒率达36.02 %。     

Bone-Bound Glucoamylase as a Biocatalyst in Bench-Scale Production of Glucose Syrups from Liquefied Cassava Starch

This research assesses the bench-scale application of a non-conventional support, bone particles, for glucoamylase (GA) immobilization and its subsequent use in cassava starch hydrolysis. Upon determining the appropriate conditions to immobilize GA onto chicken bone particles, such as pH, ionic strength, particle size, and enzyme load, bench-scale immobilization of commercial GA without further purification was performed. Under the selected conditions, 270 GA units per gram of support were adsorbed. Optimal temperature and thermal stability of immobilized GA were only slightly different from those of the free enzyme, while optimal pH became more acidic by about one unit. The feasibility of the use of this immobilized biocatalyst for high glucose syrup production from liquefied cassava starch, at bench scale in batch process using a stirred-tank reactor, was demonstrated. Repeated use of the GA-bone derivative showed that similar conversions to those achieved with soluble enzyme (dextrose equivalent = 98) were reached until the third batch and over 90% until the 25th batch.