Nonfat Dry Milk Research Articles

Does the design of spot markets matter for the success of futures markets? Evidence from dairy futures

This study provides evidence of the importance of a well‐defined and functioning spot market for the success of the associated futures market. Our analysis of hedging effectiveness and hedge ratio persistence shows that none of the United States (US) spot market indices may be hedged effectively with the Chicago Mercantile Exchange nonfat dry milk futures at short hedging horizons, whereas the New Zealand (NZ) Stock Exchange whole milk powder futures contract is an effective hedge for the Global Dairy Trade spot pricing benchmark. Four important dimensions of spot market design are identified—timeliness, market‐based measurement, forward‐spot separation, and inclusiveness.

Determination of Nitrite in Milk- and Soy-Based Nutritional Ingredients by Derivatization with 2,3-Diaminonaphthalene and Fluorescence Spectrometry.

Nitrite (NO2-) is an inorganic anion that can be found in various powdered milk- and soy-based nutritional ingredients as an incidental contaminant. Reliable determination of NO2- in nutritional ingredients is of paramount importance to ensure the safety of finished products. The derivatization reaction of NO2- with 2,3-diaminonaphthalene with the formation of fluorescent 2,3-naphtotriazole has been adapted to milk- and soy-based nutritional ingredients. The sample preparation consisted of protein precipitation with Carrez solution, simple pass-through cleanup of extracts utilizing a carbon black-based cartridge and derivatization, followed by batch fluorometry. The method was validated in six representative ingredient matrixes-i.e., whole-milk powder, nonfat dry milk, milk protein concentrate, whey protein concentrate, sodium caseinate, and soy protein isolate. Recovery values were 82-109%, whereas within-day and intermediate precision were 0.6-5.2 and 3.6-11% (RSDs), respectively. The method LOQ was 0.1 or 0.2 µg/g sodium nitrite (NaNO2), depending on the ingredient matrix. Surveyed NO2- concentration levels in 25 lots of 10 types of nutritional ingredients ranged from between less than 0.1 to 29 µg/g NaNO2. This method is proposed as a more sensitive and rugged alternative to the widely used ion chromatographic and colorimetric approaches.

CDK10 Mutations in Humans and Mice Cause Severe Growth Retardation, Spine Malformations, and Developmental Delays

In five separate families, we identified nine individuals affected by a previously unidentified syndrome characterized by growth retardation, spine malformation, facial dysmorphisms, and developmental delays. Using homozygosity mapping, array CGH, and exome sequencing, we uncovered bi-allelic loss-of-function CDK10 mutations segregating with this disease. CDK10 is a protein kinase that partners with cyclin M to phosphorylate substrates such as ETS2 and PKN2 in order to modulate cellular growth. To validate and model the pathogenicity of these CDK10 germline mutations, we generated conditional-knockout mice. Homozygous Cdk10-knockout mice died postnatally with severe growth retardation, skeletal defects, and kidney and lung abnormalities, symptoms that partly resemble the disease's effect in humans. Fibroblasts derived from affected individuals and Cdk10-knockout mouse embryonic fibroblasts (MEFs) proliferated normally; however, Cdk10-knockout MEFs developed longer cilia. Comparative transcriptomic analysis of mutant and wild-type mouse organs revealed lipid metabolic changes consistent with growth impairment and altered ciliogenesis in the absence of CDK10. Our results document the CDK10 loss-of-function phenotype and point to a function for CDK10 in transducing signals received at the primary cilia to sustain embryonic and postnatal development.

Modeling high protein liquid beverage fouling during pilot scale ultra-high temperature (UHT) processing

Ultra-high temperature (UHT) processing is where liquid foods are sterilized at temperatures at or near 135°C. Because of the relatively high temperature, UHT processes are known for developing severe foulants on heat exchange surfaces. Furthermore, there is ambiguity (and commercial variation) in the exact process temperature when UHT processing. Therefore, it was the goal of this research to quantify the effects of process temperature changes on fouling rates in a pilot UHT system. The research performed evaluated fouling when processing 20% (wt./wt.) reconstituted non-fat dry milk as a model high protein beverage. The variables of interest were process temperature (127, 132 and 138°C) and run time. Each thermal process was designed to maintain equivalent thermal processing of a model microbe (F0=7.5) by adjusting the hold tube length at each temperature. After a defined run time, foulant from the pilot system was extracted into a sodium hydroxide solution. Compositional changes in this solution were indirectly associated with the pickup of foulant from the pilot system. Statistical differences (α=0.05) in fouling rates were observes as a function of process temperature using 4 foulant indicators (active alkali, electrical conductivity, protein content and color). The temperature dependence of fouling rate fit significantly to Arrhenius models (r2 range 0.95–0.99) with activation energies ranging from 116.6 to 154.5 kJmol−1. Results provide evidence that reduction in process temperatures can significantly decrease fouling rates, therefore increasing product run times.

Novel chemiluminescent Western blot blocking and antibody incubation solution for enhanced antibody-antigen interaction and increased specificity.

Western blotting is a ubiquitous tool used in protein and molecular biology research, providing information about the presence, size, relative abundance, and state of a protein in a mixture. First, the proteins in a sample are separated by size using SDS-PAGE then transferred onto a membrane for detection with a set of primary and secondary antibodies. High-quality Western data requires high signal-to-noise ratios, which depend upon reduction of nonspecific antibody interactions. Blocking is a critical step in the Western blot method as it prevents the antibodies from binding nonspecifically to the membrane and irrelevant proteins. A solution of nonfat dry milk (NFDM) in physiological buffer is commonly used for this purpose, but does not perform well with every type of antibody and is not optimal for low-abundance proteins. We present a novel blocking solution for chemiluminescent Western blots, AdvanBlock™-chemi, which outperforms NFDM in experiments with 20 unique antibodies by increasing signal-to-noise ratios and minimizing nonspecific binding. This solution enhances protein detection by Western blot and provides consistent results for detection of low abundant and modified proteins.

Quality characteristics and acceptability of low cost weaning blends by Zambian mothers

Stunting, and to a lesser extent wasting and undernutrition, of children under five years constitutes a serious health problem in Zambia. Although non-nutritional causes such as infection and poverty importantly exacerbate these conditions, improvements in the diets of children is vital for better health. The age interval beginning at about six months is an especially vulnerable time for children, when they are being weaned from breast milk to conventionally used cultural foods. The current study reports assessments by mothers of nine experimental weaning mixtures, formulated by computer to be low cost and nutritionally superior to maize meal alone. An incomplete block design with randomization was used to compare the nine weaning food blends, differentially constituted to address specific conditions. One group of 127 mothers (or guardians) of children 6 to 27 months judged cooked porridges prepared from the blends. The alternate group of 140 mothers of children from 5 to 30 months evaluated characteristics of uncooked porridge ingredients. Statistical analyses of hedonic scale ratings and tabulation of mothers’ voluntary comments were performed. With few exceptions, blend macronutrient/energy characteristics generally conformed to proposed standards in Codex Alimentarius and other literature guidelines. Mixture levels of 20 vitamins and minerals were estimated. A rice-containing formula was most expensive and a high maize/moderate soy formulation the least costly in price assessment. Acceptability results showed that in addition to maize meal and nonfat dry milk, the most acceptable mixtures contained bambara nuts or soybeans as chief ingredients. Blends with substantial percentages of millet, sorghum, or kapenta were not ordinarily acceptable. It was observed that all four cooked porridge quality factors were significantly (p ≤ 0.01) related with each other, and that both ingredient set rating categories were likewise significantly (p ≤ 0,01) related. It is emphasized that nutrient contributions of the weaning mixtures are meant for further complementation by concurrent feeding of breast milk, by appropriate use of micronutrient powders or lipidbased micronutrient spreads, and by market or home produced foods. Acceptability results of this study may be influenced by factors such as commodity cost variations, food donations, mother education, and processing cooperatives. Key words : Weaning foods, nutrition, ingredients, porridges, quality, mothers, acceptability, Zambia

Heat stability of radio frequency dielectric heat treated low heat and high heat nonfat dry milk

The heat stability of low (LH) and high heat (HH) nonfat dry milk (NDM) that received a radio frequency dielectric heat (RFDH) treatment at 75, 80 or 85 °C for different periods of time (between 43 and 125 min) was assessed. NDM was reconstituted at 3.5% (w/w) protein. Heat stability was assessed at 140 °C by recording the heat coagulation time. Samples were evaluated at native pH, and adjusted pH from 6.4 to 7.2. LH samples heated to 75 °C or 80 °C showed greater heat stability than non-treated LH at pH 6.4 to 6.8. Data suggest that RFDH treatment of LH induced associations between whey proteins and casein micelles, which increased the heat stability in this pH region. The same effect was not observed in the HH samples, suggesting different reactions may be induced. Dry heating NDM may affect protein associations differently from liquid systems, depending upon the conditions.

Sensory Evaluation of Nonfat Dry Milk and Skim Milk Powder

Sensory Evaluation of Nonfat Dry Milk and Skim Milk Powder

A Limited Survey of Dark Chocolate Bars Obtained in the United States for Undeclared Milk and Peanut Allergens

Undeclared allergens in chocolate products have been responsible for numerous allergen-related recalls in the United States. A survey was conducted to determine the prevalence of undeclared milk and peanut in 88 and 78 dark chocolate bars, respectively. Concentrations of milk (as nonfat dry milk) or peanut in three samples of each chocolate product were determined with two milk- or peanut-specific enzyme-linked immunosorbent assay kits. In 75% of the chocolate bar products with a milk advisory statement, milk concentrations were above the limit of quantitation (2.5 μg/g [ppm]), with the majority having concentrations >1,000 ppm. An additional 67% of chocolate bars with a "traces of milk" statement contained 3 to 6,700 ppm of milk. Fifteen percent of chocolates labeled dairy free or lactose free and 25% labeled vegan were positive for milk, all with concentrations >1,000 ppm. Even for chocolates with no reference to milk on the label, 33% of these products contained 60 to 3,400 ppm of milk. The survey of chocolate products for peanuts revealed that 8% of products with an advisory statement contained peanut, with the highest concentration of 550 ppm. All nine chocolates bearing the peanut-free or allergen-free statement were negative for peanut, but 17% of chocolates with no label statement for peanut were positive for peanut at concentrations of 9 to 170 ppm. Evaluation of multiple lots of four chocolate products revealed that milk was consistently present or absent for the products investigated, but mixed results were obtained when multiple lots were tested for peanut. This study indicates that a large proportion of dark chocolate bars contain undeclared milk. The type of advisory statement or the absence of a milk advisory statement on products did not predict the amount or absence of milk protein. In contrast, a lower proportion of chocolates containing undeclared peanut was found. Consumers with food allergies should be cautious when purchasing dark chocolate products, particularly those that have an advisory label statement.

Vitamin Fortification of Fluid Milk.

Vitamin concentrates with vitamins A and D are used for fortification of fluid milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off-flavor(s) in vitamin fortified milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of fluid milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in fluid milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of fluid milk.

Physical Properties of Nonfat Dry Milk and Skim Milk Powder

Physical Properties of Nonfat Dry Milk and Skim Milk Powder

Increasing retention of vitamin D3 in vitamin D3 fortified ice cream with milk protein emulsifier

This study aimed to develop vitamin D3 fortified ice cream by incorporating vitamin D3 in an emulsified form using milk protein as emulsifier. Physicochemical stability of vitamin D3 emulsions using different milk protein emulsifiers including nonfat dry milk, sodium caseinate (Na-Cas), and whey protein isolate was investigated. Emulsion using Na-Cas had the smallest oil droplet size and the lowest creaming index throughout the storage time (P < 0.05) and was selected to fortify in full-fat, reduced-fat, and low-fat ice creams at 250 IU per serving. Vitamin D3 retention in each ice cream was determined after 0, 7, 14, 28 and 56 d of storage at −20 °C. The results indicated that the emulsified form of vitamin D3 remarkably improved vitamin D3 stability in all ice cream formulations.

The Effect of Replacing Wheat Flour with Chickpea Powder (Cicer arietinum L.) and Nonfat Dry Milk in Qualitative Properties of Muffin

The Effect of Replacing Wheat Flour with Chickpea Powder (Cicer arietinum L.) and Nonfat Dry Milk in Qualitative Properties of Muffin

POTENTIAL EFFECTS OF DUKU (LANSIUM DOMESTICUM CORR) AND LANGSAT (LANSIUM DOMESTICUM JACK) EXTRACTS ON THE GROWTH OF BIFIDOBACTERIA SPP.

Objective: Lansium domesticum Corr. is a fruit tree species belongs to the family Meliaceae. There are numerous forms of the species and grouped into two main types: Duku and Langsat. The objective of this study is to screen the ability of adding extracts of freeze-dried duku and langsat to stimulate the growth and stability of selected Bifidobacteria spp in skimmed milk.Methods: Samples were prepared by adding either 5% or 12% of oligosaccharides from duku, langsat, inulin, galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS) to 5% and 12% (w/v) reconstituted nonfat dry milk (NDM), respectively. The specific growth rates (µ) for each sample were calculated. All experiments were replicated ten times.Results: The mean doubling time (Td) for Bifidobacterium longum, was lowest in the presence of freeze-dried duku and langsat compared to GOS, FOS and inulin. Retention of the viability of five Bifidobacterium species was greatest in the presence of freeze-dried duku and langsat followed by GOS, FOS and inulin. The highest percentage of acetic and lactic acids were produced by B. longum, B. infantis and B. adolescentis with freeze-dried duku and langsat. The pattern of results was similar to the commercial product, oligosaccharides (inulin, GOS and FOS). Conclusion: Therefore, this study provides promising results on promoting growth and probiotic activity of natural oligosaccharides compound from freeze-dried duku and langsat.

Condensed milk storage and evaporation affect the flavor of nonfat dry milk.

Unit operations in nonfat dry milk (NFDM) manufacture influence sensory properties, and consequently, its use and acceptance in ingredient applications. Condensed skim milk may be stored at refrigeration temperatures for extended periods before spray drying due to shipping or lack of drying capacity. Currently, NFDM processors have 2 options for milk concentration up to 30% solids: evaporation (E) or reverse osmosis (RO). The objective of this study was to determine the effect of condensed milk storage and milk concentration method (E vs. RO) on the flavor of NFDM and investigate mechanisms behind flavor differences. For experiment 1, skim milk was pasteurized and concentrated to 30% solids by E or RO and then either stored for 24h at 4°C or concentrated to 50% solids by E and spray dried immediately. To investigate mechanisms behind the results from experiment 1, experiment 2 was constructed. In experiment 2, pasteurized skim milk was subjected to 1 of 4 treatments: control (no E), heated in the evaporator without vacuum, E concentration to 30% solids, or E concentration to 40% solids. The milks were then diluted to the same solids content and evaluated. Volatile compounds were also measured during concentration in the vapor separator of the evaporator. Sensory properties were evaluated by descriptive sensory analysis and instrumental volatile compound analysis was conducted to evaluate volatile compounds. Interaction effects between storage and method of concentration were investigated. In experiment 1, E decreased sweet aromatic flavor and many characteristic milk flavor compounds and increased cardboard and cooked flavors in NFDM compared with RO. Liquid storage increased cardboard flavor and hexanal and octanal and decreased sweet aromatic flavors and vanillin concentration. Results from experiment 2 indicated that the characteristic milk flavors and their associated volatile compounds were removed by the vapor separator in the evaporator due to the heat and vacuum applied during concentration. These results demonstrate that off-flavors are significantly reduced when RO is used in place of E and storage of condensed milk is avoided.

The effect of spray-drying parameters on the flavor of nonfat dry milk and milk protein concentrate 70.

Unit operations during production influence the sensory properties of nonfat dry milk (NFDM) and milk protein concentrate (MPC). Off-flavors in dried dairy ingredients decrease consumer acceptance of ingredient applications. Previous work has shown that spray-drying parameters affect physical and sensory properties of whole milk powder and whey protein concentrate. The objective of this study was to determine the effect of inlet temperature and feed solids concentration on the flavor of NFDM and MPC 70% (MPC70). Condensed skim milk (50% solids) and condensed liquid MPC70 (32% solids) were produced using pilot-scale dairy processing equipment. The condensed products were then spray dried at either 160, 210, or 260°C inlet temperature and 30, 40, or 50% total solids for NFDM and 12, 22, or 32% for MPC70 in a randomized order. The entire experiment was replicated 3 times. Flavor of the NFDM and MPC70 was evaluated by sensory and instrumental volatile compound analyses. Surface free fat, particle size, and furosine were also analyzed. Both main effects (30, 40, and 50% solids and 160, 210, and 260°C inlet temperature) and interactions between solids concentration and inlet temperature were investigated. Interactions were not significant. In general, results were consistent for NFDM and MPC70. Increasing inlet temperature and feed solids concentration increased sweet aromatic flavor and decreased cardboard flavor and associated lipid oxidation products. Increases in furosine with increased inlet temperature and solids concentration indicated increased Maillard reactions during drying. Particle size increased and surface free fat decreased with increasing inlet temperature and solids concentration. These results demonstrate that increasing inlet temperatures and solids concentration during spray drying decrease off-flavor intensities in NFDM and MPC70 even though the heat treatment is greater compared with low temperature and low solids.

Does the Design of Spot Markets Matter for the Success of Futures Markets? Evidence from Dairy Futures

This study provides evidence of the importance of a well-defined and functioning spot market for the success of the associated futures market. The United States (US) spot market for nonfat dry milk has several distinct pricing benchmarks, whereas the New Zealand (NZ) market has a single spot reference price. Our analysis of hedging effectiveness shows that none of US spot market benchmarks may be hedged effectively with the Chicago Mercantile Exchange nonfat dry milk futures, whereas the NZ Stock Exchange whole milk powder futures contract is an effective hedge for the Global Dairy Trade spot pricing benchmark. Four important dimensions of spot market design are identified – timeliness, market-based measurement, forward-spot separation, and inclusiveness.

Evaluation of Commercial Milk-Specific Lateral Flow Devices

The requirement for validation of allergen cleaning processes is increasing. The use of lateral flow devices (LFDs) to identify allergens has rapidly expanded, but the best practices for use of these devices are still developing. The goal of this study was to compare commercially available milk-specific LFDs and a general protein identification method. Five milk proteins and seven milk-derived ingredients were tested at several concentrations with eight milk-specific LFDs and a general protein identification kit. Nonfat dry milk (NFDM) was prepared at 100 to 10,000 ppm of milk protein and analyzed by the LFDs to determine the concentration at which a false-negative result (overload concentration or hook effect) was obtained. NFDM was also prepared in 0.025 M phosphate-buffered saline (pH 7.4, 0.85% NaCl) and applied to stainless steel panels (100, 30, 10, or 3 μg of NFDM protein) with various drying methods and sampled with various swab methods to determine the level of detectability. Several total milk LFD kits did not detect whey proteins or whey-derived ingredients. The overload concentration of the various kits ranged from 100 to 10,000 ppm of milk protein. The small dynamic range observed for some kits would necessitate multiple dilutions of a sample to ensure that the result would fall within the range of detection. For swab sampling of stainless steel for LFD analysis, milk protein residues from surfaces onto which the residues were dried with high heat were more difficult to detect than were residues dried with low heat. No differences in sensitivity were observed as a result of moistening the residue or the swab before sampling. These results highlight the importance of understanding the detection capabilities of LFDs as indicated by the variability in the performance of the milk-specific LFDs tested.

Commercial Milk Enzyme-Linked Immunosorbent Assay (ELISA) Kit Reactivities to Purified Milk Proteins and Milk-Derived Ingredients.

Numerous commercial enzyme-linked immunosorbent assay (ELISA) kits exist to quantitatively detect bovine milk residues in foods. Milk contains many proteins that can serve as ELISA targets including caseins (α-, β-, or κ-casein) and whey proteins (α-lactalbumin or β-lactoglobulin). Nine commercially-available milk ELISA kits were selected to compare the specificity and sensitivity with 5 purified milk proteins and 3 milk-derived ingredients. All of the milk kits were capable of quantifying nonfat dry milk (NFDM), but did not necessarily detect all individual protein fractions. While milk-derived ingredients were detected by the kits, their quantitation may be inaccurate due to the use of different calibrators, reference materials, and antibodies in kit development. The establishment of a standard reference material for the calibration of milk ELISA kits is increasingly important. The appropriate selection and understanding of milk ELISA kits for food analysis is critical to accurate quantification of milk residues and informed risk management decisions.

Characterising variances of milk powder and instrumentation for the development of a non-targeted, Raman spectroscopy and chemometrics detection method for the evaluation of authenticity

ABSTRACTThere is a need to develop rapid tools to screen milk products for economically motivated adulteration. An understanding of the physiochemical variability within skim milk powder (SMP) and non-fat dry milk (NFDM) is the key to establishing the natural differences of these commodities prior to the development of non-targeted detection methods. This study explored the sources of variance in 71 commercial SMP and NFDM samples using Raman spectroscopy and principal component analysis (PCA) and characterised the largest number of commercial milk powders acquired from a broad number of international manufacturers. Spectral pre-processing using a gap-segment derivative transformation (gap size = 5, segment width = 9, fourth derivative) in combination with sample normalisation was necessary to reduce the fluorescence background of the milk powder samples. PC scores plots revealed no clear trends for various parameters, including day of analysis, powder type, supplier and processing temperatures, while the largest variance was due to irreproducibility in sample positioning. Significant chemical sources of variances were explained by using the spectral features in the PC loadings plots where four samples from the same manufacturer were determined to likely contain an additional component or lactose anomers, and one additional sample was identified as an outlier and likely containing an adulterant or differing quality components. The variance study discussed herein with this large, diverse set of milk powders holds promise for future use as a non-targeted screening method that could be applied to commercial milk powders.