Cream Powder Research Articles

Headspace solid-phase microextraction and on-fibre derivatization of primary aromatic amines for their determination by pyrolysis to aryl isothiocyanates and gas chromatography-mass spectrometry

A sensitive and solvent-free procedure for the determination of aromatic amines in environmental and food samples was studied using solid-phase microextraction (SPME) for on-fibre derivatization and gas chromatography-mass spectrometry (GC-MS). The analytical procedure involved headspace impregnation of allyl isothiocyanate on the SPME fibre and then extraction/derivatization of aromatic amines by placing impregnated fibre in the headspace of the sample. The allyl thiourea derivatives were pyrolyzed in the injection port of the GC and the aryl isothiocyanates thus formed were chromatographed. SPME parameters such as selection of coating material, extraction/derivatization time and temperature were optimized. The optimum extraction was obtained using a divinylbenzene/carboxen/polydimethylsiloxane fibre placed for 20 min in the headspace of the sample heated to 70 °C. This method increased the extractability and detectability of aromatic amines from complex environmental and food samples. The calibration curves for derivatized amines were linear in the range 0.05–100 μg L−1 with correlation coefficients in the range 0.9946–0.9994 and limits of detection in the range 6–180 ng L−1. Many real samples including food colours, ice cream powder, soft drink concentrate, and industrial area sand have been analyzed and were found to contain elevated levels of aromatic amines.

OCCURRENCE OF MYCOBIOTA AND AFLATOXIN M1 IN SOME DRIED DAIRY PRODUCTS

A total of 110 samples of dried dairy products represented as full cream milk powder (50 sachets) were randomly collected from groceries, supermarkets and dried casein (30) and dried whey (30) in sterile polyethylene bags from large factories in Alexandria Governorate. All samples were still valid for consumption as shelf -life is at least to be one year from production time. The collected samples were transmitted to the laboratory for preparation. The samples were examined to determine the levels of fungal contamination and the possible presence of aflatoxin M1. The obtained data pointed out that 40, 36.67 and 43.33% of the examined samples of milk powder, dried casein and dried whey were contaminated with molds with average counts of 2.2 X10 3 , 4.2 X 10 2 , and 2.1 X 10 2 /g, respectively. Aspergillus was the prevalent genus encountered in the examined samples followed by genus penicillium. 5 out of 14 isolated strains of A. flavus (35.71%) proved to be aflatoxin B1 (AFB1) producers with different concentrations. Aflatoxins M1 could be detected in the examined milk powder, dried casein and dried whey samples, using ELISA, with concentration levels of 0.07-0.6, 0.02-0.06 and 0.03-0.08 µg|kg, respectively. All positive samples were not complied with Egyptian Standards (1990) which stated that milk and milk products should be free from any aflatoxins. So, efforts have to be made to prevent mold growth and aflatoxins production along the entire food chain specially food related to children.

Mobility of inorganic nanoparticles in soft matter

The 100 nm hematite Fe2O3 particles in gelatin gel, dense water solution of sugar, commercial paints, foam, cosmetic cream and friable powder exhibit the mobility in the range of mm/s which was determined from the analysis of the resonance absorption line shape. In the solution of sugar the movement is correlated for particle–particle distance less then 300 nm. The Mossbauer spectroscopy of the iron bearing nanoparticles is proposed as a novel experimental technique for the investigation of the dynamical and structural properties of the soft matter at the mesoscoipic scale.

The chemical composition of some kinds of local soybean Glycine max and its utilization in manufacturing supporting cereal baby foods

This study was conducted on five kinds of local soybean seeds (Ibaa, Hawija, Taqa.2, Lee74 and Hassan). The chemical analysis results showed that Hawija soybean has the highest percent of protein which was 38-08%, The amino acid percent was also higher than the other kinds(lysine, Thereonine and Tryptopham), and being 389,250,81 mg/gm nitrogen respectively Both amino acids were important for child nutrition. Hawija was selected, being the best for proteins and basic amino acids, and was utilized in preparation of the adjunct baby food formula. Eighteen formulas had been prepared by using soybean flour kind(Hawija), wheat flour kind (Abu gharib) and full fat powder milk (NIDO). Each formula contained 20% protein as recommended by F.A.O, W.H.O and Iraqi standard. The chemical analysis results showed that formulas had low moisture content(3.18-3.60%) and high carbohydrate content (59.10-60.12%), The protein and fat content was 19.23-20.81 and 14-4.35% respectively. The content of ash of the formulas were(2.50-3.23%),the calorie value was 430.17-432.42 K.cal /100 gm sample.the sensory evaluation showed that, the formulas with high contain in whole cream powder of milk or wheat flour, obtained higher sensory evaluation grades.

The chemical composition of some kinds of local soybean Glycine max and its utilization in manufacturing supporting cereal baby foods

This study was conducted on five kinds of local soybean seeds (Ibaa, Hawija, Taqa.2, Lee74 and Hassan). The chemical analysis results showed that Hawija soybean has the highest percent of protein which was 38-08%, The amino acid percent was also higher than the other kinds(lysine, Thereonine and Tryptopham), and being 389,250,81 mg/gm nitrogen respectively Both amino acids were important for child nutrition. Hawija was selected, being the best for proteins and basic amino acids, and was utilized in preparation of the adjunct baby food formula. Eighteen formulas had been prepared by using soybean flour kind(Hawija), wheat flour kind (Abu gharib) and full fat powder milk (NIDO). Each formula contained 20% protein as recommended by F.A.O, W.H.O and Iraqi standard. The chemical analysis results showed that formulas had low moisture content(3.18-3.60%) and high carbohydrate content (59.10-60.12%), The protein and fat content was 19.23-20.81 and 14-4.35% respectively. The content of ash of the formulas were(2.50-3.23%),the calorie value was 430.17-432.42 K.cal /100 gm sample.the sensory evaluation showed that, the formulas with high contain in whole cream powder of milk or wheat flour, obtained higher sensory evaluation grades.

Surface composition of industrial spray-dried milk powders. 3. Changes in the surface composition during long-term storage

The changes in the surface composition of industrial spray-dried milk powders (skim milk powder, whole milk powder and cream powder) during long-term storage were investigated. The powders were stored in the conditions, which are more likely for commercial circumstances, for 6 months and the surface composition of the powders was analyzed before and after storage using electron spectroscopy for chemical analysis (ESCA). For the fat-containing powders (whole milk powder and cream powder), the various milk fat fractions (surface free-fat, inner free-fat and encapsulated fat) were also extracted before and after storage, and analyzed for their fatty acid and triglyceride compositions to evaluate whether there was a release of fat onto the powder surface during storage and if this causes changes in the melting characteristics of the fat present on the powder surface. The structure of the powders and the physical state of the lactose present in the powder were studied before and after storage by scanning electron microscopy (SEM) and X-ray diffractometer (XRD), respectively. The results showed that the lactose present in the powders remained in the amorphous state over the storage, and therefore no significant changes in structure and surface composition of the powders occurred. However, a release of encapsulated low-melting triglycerides towards the surface of powder during storage was observed in the fat-containing powders, thereby the melting points of the surface free-fat and the inner free-fat were lowered. This phenomenon was observed in both whole milk powder and cream powder, but more significant changes were observed in CP.

Inhibition of adhesion of Streptococcus mutans to hydroxylapatite by commercial dairy powders and individual milk proteins

The aim of this study was to investigate the inhibitory effect of various dairy powders and milk constituents on the adhesion of a clinical isolate of Streptococcus mutans to hydroxylapatite (HA), an analogue of tooth enamel. Adhesion of a microorganism to a cell surface such as epithelial cells or tooth enamel is considered to be the first step in pathogenesis. Inhibiting this process may have therapeutic effects in vivo. The adherence assays were performed by incubating S. mutans with HA in the presence of each test material for 45 min, followed by centrifugal separation of the HA. Unbound bacteria were then quantified using a fluorescent dye. Sweet and Acid WPC80, buttermilk powder and cream powder were found to very effectively inhibit adherence of S. mutans to phosphate-buffered saline coated HA (PBS-HA). Sodium caseinate and the casein fractions α-,β- and κ-casein were also found to show high levels of anti-adhesive activity. A selection of test materials were assessed using saliva-coated HA (S-HA), and similar trends were observed. The results suggest commercial dairy powders, and certain milk proteins, can inhibit adhesion of S. mutans to HA and may have potential to control dental caries.

English

Quick test for quality check of processed food will be handy for Defence Forces. Aciditybeing one of the most important quality parameters, as per the ASC, BIS, PFA specifications,limits have been laid down as not to exceed 2 per cent in meat and fish products, 0.1 per centin cereal products, 1.25 per cent in ice cream powder, 1.5 per cent in milk powder, 0.3 per centin sweetened condensed milk, and 0.15 per cent in butter. In the present study, a simple, quick,semi-quantitative test has been developed for checking acidity in processed foods to ascertaintheir quality. The test is based on a colour reaction with the sample. The test solution givesblue to green to yellow colour depending on the concentration of acid in the sample. Greencolour is the cut-off point for non-acceptance. The large number of samples of meat (155), fishproducts (48), cereal products (222), ice cream powder (200), butter (200), milk powder (200) andsweetened condensed milk (202) were analysed by the quick test method and the results werecompared with those from the standard titrimetric method. Acidity ranged form 0.68 per centto 2.40 per cent in meat products, 0.70 per cent to 2.50 per cent in fish products, 0.06 per centto 1.25 per cent in butter, 0.60 per cent to 1.91 per cent in milk powder, 0.05 per cent to 0.54 percent in ice cream powder, 0.32 per cent to 0.60 per cent in sweatened condensed milk, 0.05 percent to 1.10 per cent in cereal products. Some samples were found to be unacceptable havingacidity more than the specified limits. The data were analysed statistically and the quick testwas found to correlate very well with the standard titrimetric method.

Chemical, sensory and microbiological changes of gamma irradiated coconut cream powder

A study was carried out to determine optimum decontamination dose for a locally manufactured coconut cream powder. Samples were gamma irradiated (0–15 kGy) and ageing process was achieved using GEER oven at 60 °C for 7 days, which is equivalent to one-year storage at room temperature. Iodine value (IV), ranging from 4.8 to 6.4, was not affected by radiation doses and storage, however peroxide value and thiobarbituric acid (TBA) generally increased with radiation doses. In most samples, peroxide value (meq/kg) reduced after storage, whilst the TBA (mg malonaldehyde/kg), indicator for product quality, slightly increased. The sensory evaluation conducted using 25 taste panellists indicated that scores on odour, creamy taste and overall acceptance for all irradiated samples at more than 5 kGy were significantly lower ( P<0.05) than the control. However, the panellists could not detect any significant differences among the irradiation doses ( P>0.05). All stored products were significantly different in colour, creamy taste, odour and overall acceptance ( P<0.05) when compared to the non-stored non-irradiated control. Microbiological count of the samples prior to irradiation was in the range of 1×10 2–1.7×10 3 cfu/g with no detection of Salmonella sp. and Escherichia coli. No microbial colonies were detected after irradiation. Based on the TBA and overall sensory acceptance, gamma irradiation of 5 kGy was found to be the optimum dose and lower doses can be considered to decontaminate coconut cream powder.

Stickiness curves of high fat dairy powders using the particle gun

High fat (>42%) dairy powders are inherently sticky due to their high levels of liquid surface fat. Incorrect operating conditions when spray drying these powders can rapidly lead to blockages. The particle gun was used to characterise the stickiness curves of high fat cream and cheese powders. Stickiness was shown to increase with increasing temperature to a maximum at 50 °C after which it decreased until no stickiness was observed above 68 °C. A dramatic increase in stickiness for the powders was found when the relative humidity of the air was increased past a certain critical point for each temperature. This was attributed to the lactose component of the powder exceeding its glass transition temperature by a critical amount. Best estimates of the ( T− T g) crit. values for White Cheese Powder, Low Fat Cream Powder and High Fat Cream Powder were 28, 37 and 38 °C, respectively.

Effect of surface composition on the flowability of industrial spray-dried dairy powders

The surface composition of four industrial spray-dried dairy powders (skim milk powder, whole milk powder, cream powder and whey protein concentrate) was estimated by electron spectroscopy for chemical analysis (ESCA), and its influence on powder flowability was studied. It was found that skim milk powder flows well compared to the other powders because the surface is made of lactose and protein with a small amount of fat, whereas the high surface fat composition inhibits the flow of whole milk, cream and whey protein powders. However, the poor flowability of the powders with high surface fat coverage was drastically improved by removal of fat present on the surface through a brief wash with petroleum ether. The results obtained indicate that, although there are several parameters including particle size, which influence the flowability of powders, the flowability of powders is strongly influenced by the surface composition of powders, particularly for fat-containing powders.

Melting characteristics of fat present on the surface of industrial spray-dried dairy powders

The melting characteristics of the fat present on the surface (surface free-fat) of two industrial spray-dried dairy powders (cream powder and whole milk powder) were investigated in comparison with those of other milk fat fractions present in the powder, such as free-fat from the interior of the powder particle (inner free-fat) and encapsulated fat. The melting characteristics of the milk fat fractions were studied by fatty acid composition, melting profile and solid fat content profile. The results indicated that all milk fat fractions including surface free-fat contained various triglycerides with melting points ranging from −40 to +40 °C. However, some fractionation was observed among the different milk fat fractions. The free-fat fractions (surface free-fat and inner free-fat) had a greater proportion of high-melting triglyceride species than the encapsulated fat. Furthermore, the high-melting triglyceride species present in the free-fat fractions were slightly accumulated at the surface of powder. This phenomenon was observed in both cream powder and whole milk powder and its effect on wetting time was established. This indicates that manipulation of the surface fat content during drying operation may hold the key to functionality improvement.

Influence of milk components on properties and consumer acceptance of milk chocolate

The objective of the study was to assess the effects of various milk components on chocolate quality, defined by measurable properties and decisively by consumer liking.The choice of milk products considered different types, technologies and suppliers. Samples produced under standardised conditions were analysed for particle size, flow properties, colour and by a trained sensory panel. Consumer testing determined overall liking. Results revealed that milk ingredients influence consumer liking of milk chocolate through the quality driving parameters of particle size/sandiness, viscosity/melting mouthfeel and milk flavour. Chocolates made from milk products that contain high amounts of free fat – e.g. skim milk powder plus anhydrous milk fat – scored better than those using bound fat – e.g. whole milk powder. Milk fat status had more influence than differences between spray and roller-dried powders. High free fat cream powders were most suitable for cream chocolates. All milk components need to be free from off-notes that require sensory checks. Fillers like lactose could replace some sucrose, and whey protein concentrate can partially replace skim milk powder.

Surface characterization of four industrial spray-dried dairy powders in relation to chemical composition, structure and wetting property

The surface composition of powders is expected to play an important role during its end use. Understanding the mechanism of the powder surface formation in terms of the compositional aspect and the ability to control the surface composition will be highly useful in milk powder quality improvement and new product development. For a preliminary study, the surface compositions of four industrial spray-dried dairy powders (skim milk powder, whole milk powder, cream powder and whey protein concentrate) manufactured for consumer use, were studied by means of electron spectroscopy for chemical analysis (ESCA). It was found that all the powders have relatively high surface fat coverage. In order to verify these results and to demonstrate the usefulness of ESCA in analysing the surface composition of dairy powders, fresh powders and fat extracted powders were subjected to the following experiments: measurement of powder surface composition, surface structure studies, fat localization studies, wetting test and measurements of surface oxygen uptake during storage. The results obtained indicate that the ESCA measurements are very reliable and the surface composition of the industrial spray-dried dairy powders estimated by ESCA is also expected to be reliable. In addition, the results showed fat globules encapsulated by protein or proteins are preferentially located underneath the surface fat.

Determination of Phosphatidylethanolamine, Phosphatidylcholine and Lyso-types in Foods by HPLC

(1) A sensitive rapid method was established for determining phosphatidylethanolamine, phosphatidylcholine and lyso-types in foods by HPLC.(2) A Nucleosil 50-7 column, was used. Elution was carried out with a mixture of acetonitrile, methanol and 85% phosphoric acid (760 : 100 : 9) as the mobile phase. The UV detector was set at 202nm.(3) The recovery phospholipids added to lard, margarine, cream powder and milk at 0.1% or 0.5% was from 85.7103% and the coefficient of variance ranged from 0.713.47%. The detection limits were 0.002% for PE and PC and 0.005% for LPE and LPC.

Influence of Oxygen Concentration on the Flavour and Chemical Stability of Cream Powder

Descriptive sensory analysis and analysis of hexanal content were performed on cream powder stored in darkness at different oxygen concentrations at 30 °C for up to 45 weeks. The headspace of the samples contained 209 (air), 13, 3.6, 0.4 or 0.3 m/L oxygen/L headspace gas. All samples stored with reduced oxygen content were, with one exception, significantly different from the air-packed sample after 25 as well as after 45 weeks of storage, both in their hexanal concentration and according to sensory analysis. However, there were no significant sensory differences between the samples stored with reduced oxygen for 25 or 45 weeks. Analysis of the hexanal concentration in the samples was a more sensitive method than sensory analysis for detecting differences between samples stored for the same length of time. Furthermore, some of the samples with reduced oxygen concentration were found to differ significantly in their hexanal concentration. Significant differences between samples before storage and samples stored for 25 or 45 weeks, regardless of oxygen concentration, were found by both sensory and chemical analyses.

Influence of Oxygen Concentration and Light on the Oxidative Stability of Cream Powder

The production of volatile oxidation products and consumption of oxygen were measured in cream powder stored for 35 weeks at 30 °C in darkness or exposed to fluorescent light. The headspace of the bottles contained either air (209 mL O2/L) or 13, 3.5, 0.4 or 0.3 mL/L oxygen in nitrogen. The exposure to light strongly influenced both the rate of hexanal production and oxygen consumption. After the first 5 weeks of storage in light, significantly different oxygen-dependent increases in hexanal were found for all samples. Although the samples stored in darkness showed a much smaller hexanal increase, it was still significant during storage. After 35 weeks of storage, the dark-stored sample in air showed a highly significant larger hexanal increase than all the other samples stored in darkness, but after the same storage period, the hexanal increase in the 13, 3.6 and 0.4 mL O2/L samples was the same. The production of the Strecker aldehyde, 3-methylbutanal, was found to depend on light and to some extent on oxygen concentration, which indicates that lipid oxidation also influenced the conditions of the Maillard reaction.

Influence of Oxygen Concentration on the Storage Stability of Cream Powder

The influence of low oxygen concentrations on lipid oxidation during storage of cream powder was studied. The powder was packed with oxygen concentrations of 209 mL/L, 17 mL/L, 8.3 mL/L, 3.4 mL/L, 1.5 mL/L, 0.7 mL/L and 0.6 mL/L and stored in darkness at 30 °C for 29 weeks. To follow oxidation, the formation of volatile oxidation products and oxygen consumption were measured. After 7 weeks of storage a significant (P<0.01) hexanal development was already seen in all the samples, and the hexanal content was directly related to the initial oxygen content, with one exception, the 0.6 mL/L sample, which had a slightly (but not significantly,P>0.05) higher hexanal content than the 0.7 mL/L sample. There were only small differences in hexanal formation between the samples packed with oxygen concentrations below 3.4 mL/L. This could be due to a more pronounced influence of oxygen diffusion at these low levels of oxygen, leading to a diffusion-controlled oxidation. Other volatiles, not produced by lipid oxidation, also increased during storage. The formation of Strecker aldehydes was found to be oxygen-dependent, whereas the formation of 2-alkanones was not. Measurement of oxygen consumption was not sufficient to detect differences in oxidation rate between the samples packed with 17 mL/L oxygen and less.

Effects of feed fat on the composition and technological properties of milk and milk fat

The aim of the study was to establish how the addition of rapeseed oil to a processed feed mixture affects the milk produced on commercial dairy farms as well as the composition and quality of the products made from that milk. In this study, replacing grain with processed feed mixture to which 2 or 4 % rapeseed oil had been added was not found to affect milk yield or composition to any considerable extent. As a result of the test feedings, the amounts of myristic and palmitic acid in the milk fat decreased and those of stearic and unsaturated fatty acids increased. This change in fatty acid composition can be viewed as nutritionally desirable, and it also had a good effect on the consistency of butter. During the second test period (4 % rapeseed oil) the cutting firmness figures of the butter were lowest, and in sensory evaluations the butter was also found to have the best consistency. The test feeding had a slight beneficial effect on the composition of milk protein. The amount of casein nitrogen grew and that of NPN fell. However, the test feeding was not found to affect the quality of the market milk, cream, cheese or milk powder.

Development of Milk Powder Reference Materials Certified for Aflatoxin Mt Content (Part II): Certification of Milk Powder RM 283

The development of a full cream milk powder reference material, certified for its aflatoxin M1 content (target concentration: 0.1 microgram/kg), is described. The material (RM 283) was prepared and certified within the Reference Material Programme of the Community Bureau of Reference, along with other members of a series of milk powder reference materials. Homogeneity, evaluated by determining the aflatoxin M1 content of 30 units, was found to be acceptable (coefficient of variation of analysis results: 9.1%); stability has been demonstrated in a long-term study. The certification exercise involved 7 laboratories. Calibration, control of recoveries, blank values, and independence of the replicate measurements were emphasized. All sets of results of the certification exercise were accepted for statistical evaluation. A certified value for the aflatoxin M1 content: 0.09(+0.04)(-0.02) micrograms/kg was derived. The certification of RM 283 completes the series of 4 milk powder reference materials having certified aflatoxin M1 contents.