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Few studies have addressed the effects of package material in the absence of light on contributions to fluid milk flavor. The objective of this study was to compare the sensory and chemical properties of fluid milk packaged in paperboard cartons, low-density polyethylene, high-density polyethylene (HDPE), polyethylene terephthalate (PET), linear low-density polyethylene (LLDPE), and glass. Pasteurized (high temperature short time, 77°C for 25 s) skim and whole milk were filled (280 mL ± 10 mL) into paperboard cartons, low-density polyethylene, HDPE, PET, LLDPE, and glass (control). Milks were stored at 4°C in the dark and sampled at d 0, 5, 10, and 15. Descriptive analysis was applied to document sensory profiles at each time point, and volatile compounds were extracted and identified by solid-phase microextraction with gas chromatography mass spectrometry and gas chromatography-olfactometry. Tetrad tests with consumers were conducted at d 10. Both skim and whole milks packaged in cartons had noticeable paperboard flavor by d 5 and higher levels of hexanal than skim and whole milks in other package types at d 5. Skim milks packaged in paperboard cartons and LLDPE had distinct refrigerator/stale flavor compared with milks in the other package types, concurrent with increased levels of refrigerator/package-related compounds including styrene, acetophenone and 2-ethyl-1-hexanol. Milks packaged in glass, PET and HDPE were not distinguished by consumers at d 10 post-processing. Package type influences fluid milk flavor, and these effects are greater in skim milk compared with whole milk. Paperboard cartons do not preserve milk freshness, as well as PET, HDPE, or glass, due to flavor migration and scalping. Glass remains an ideal barrier to preserve fluid milk flavor, but in the absence of light, HDPE and PET provide additional benefits while also maintaining fluid milk flavor., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Conscious consumerism is growing, along with consumer demand for socially conscious dairy products or dairy alternatives. To successfully position dairy products (especially conventional dairy) in this changing marketplace, dairy producers and processors must understand how to strategically use both on- and off-package messaging aligned with consumer perceptions. However, consumer perception of attributes such as sustainable, natural, and healthy is complex, and varies between product categories as well as among products within a category. The objective of this study was to characterize consumer definitions of the terms "sustainable," "natural," and "healthy" as they pertain to dried dairy ingredients. To meet this objective, we conducted an online survey with 3 maximum difference scaling exercises to determine the importance of 63 label claims to consumer definitions of the terms sustainable, natural, and healthy. The role of priming with dried ingredient processing information on consumer perception of these terms was also explored. Within the dried dairy ingredients category, there is extensive cognitive overlap between the terms sustainable, natural, and healthy. Priming did not affect consumer definitions of any of these terms. Certification-related claims were considered among the least important claims for consumer definitions of sustainable, natural, and healthy, whereas claims that were simple to read and visualize were considered among the most important. Claims related to animal welfare and happiness or simple, minimal ingredients and processing were considered by consumers to be important for all 3 terms. For each of these terms, there was a cluster of consumers who defined the term primarily by simple ingredients and minimal processing, and another cluster who defined the term primarily by happy cows and conscious farming practices. The terms sustainable and healthy each had a third, unique consumer cluster. This third definition cluster defined sustainability primarily by environmental effects, whereas this cluster defined healthy primarily in fitness and nutrition terms. Age and to a lesser extent, gender, affected importance placed on these 3 terms and also affected definition of the term. Understanding these consumer definitions provides insight on how to formulate marketing and educational messaging to speak to each consumer segment., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Plant-based dairy alternative beverage sales have increased in recent years. Plant-based dairy alternatives often advertise on a platform of sustainability and environmental commitment. To successfully position and market dairy products in this competitive environment, dairy companies must understand the consumer definition of and importance placed on sustainability, as well as communicate sustainability information effectively. The objective of this study was to characterize consumer perception of the sustainability of milk and dried dairy ingredients and their respective plant-based alternatives. Focus groups and 2 online surveys were conducted. In the first survey, maximum difference scaling was used to rank the importance of specific dairy product attributes to sustainability, along with an exercise in which respondents selected whether a fluid milk or protein powder product was sustainable. A follow-up survey included 2 exercises in which respondents selected whether generic dairy products or dried dairy ingredients were sustainable, natural, healthy, trustworthy, or ethical. Over half of dairy product consumers reported that they looked for sustainability-related information. Consumers who purchased both plant-based dairy alternative and dairy products placed a higher self-reported importance on sustainability than those who purchased dairy products only. Focus group and survey maximum difference scaling results identified 5 key attributes for sustainability: minimal carbon footprint/greenhouse gas emissions, few/no preservatives, animal happiness and welfare, and simple/minimal ingredients. Plant-based dairy alternatives followed by fluid milk and protein powders were considered more sustainable than dairy products, but package type and organic status also played a role in consumer sustainability perception. Product labels were the most common source of sustainability information, although consumers also sought information on websites affiliated and unaffiliated with dairy companies. There was cognitive overlap among the terms sustainable, natural, healthy, ethical, and trustworthy as they relate to dairy products, but consumers used the terms distinctly. Consumers perceived differences in these terms between general categories of dairy as well as among products in a specific dairy category. Dairy companies may be able to differentiate themselves by helping consumers make these choices by simplifying sustainability-related messaging and by maintaining open, transparent communication regarding sustainability., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Protein bars are one product that meet consumer demands for a low-carbohydrate, high-protein food. With such a large market for protein bars, producers need to find the correct texture and sweetness levels to satisfy consumers while still delivering a high-protein, low-carbohydrate bar. In the bar industry, bar hardening is a major concern, and currently the effects of non-nutritive sweeteners on bar hardening is unknown. Due to the negative implications of bar hardening, it is important to investigate the sweetener-protein relationship with bar hardening. The objective of this study was to characterize the effects of sweetener and protein source on flavor, texture, and shelf life of high-protein, low-carbohydrate bars. The iso-sweet concentration of sweeteners (sucralose, sucrose, monk fruit, stevia, and fructose) in pea protein (PP), milk protein (MP) and whey protein isolate (WPI) bars were established using magnitude estimation scaling and 2-alternative forced-choice testing. Descriptive analysis and temporal check-all-that-apply methods were then applied to determine flavor and temporal differences between the protein bars. Finally, an accelerated shelf life study was completed to understand how sweetener and protein types affect the shelf life of protein bars. The 15 protein bars formulated at iso-sweet concentration were all stored at 35°C and 55% humidity for 35 d, and measurements were taken every 7 d, beginning at d 1 (d 1, 7, 14, 21, 28, and 35). Bars made with MP required significantly less sweetener, compared with PP and WPI, to reach equal sweetness. Bars sweetened with stevia or monk fruit had distinct bitter and metallic tastes, and sucralose had a low metallic taste. Bars made with WPI were the most cohesive, and PP and WPI bars were more bitter and metallic compared with MP bars. Bars made with WPI and fructose were initially the hardest, but after d 14 they scored at parity with PP sucrose. There were no significant differences among bars in terms of hardness by d 21. Bars made with WPI were consistently denser at all time points than bars made with PP or MP. Bars made with PP were the driest and least cohesive and had the fastest rate of breakdown in the study. Non-nutritive sweeteners did not have a negative effect on bar hardness in low-carbohydrate, high-protein bars. Findings from this study can be applied to commercially produced protein bars for naturally sweetened bars with different protein types without negative effects on protein bar texture., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Much of the fluid whey produced in the United States is a by-product of Cheddar cheese manufacture and must be bleached. Benzoyl peroxide (BP) is currently 1 of only 2 legal chemical bleaching agents for fluid whey in the United States, but benzoic acid is an unavoidable by-product of BP bleaching. Benzoyl peroxide is typically a powder, but new liquid BP dispersions are available. A greater understanding of the bleaching characteristics of BP is necessary. The objective of the study was to compare norbixin destruction, residual benzoic acid, and flavor differences between liquid whey and 80% whey protein concentrates (WPC80) bleached at different temperatures with 2 different benzoyl peroxides (soluble and insoluble). Two experiments were conducted in this study. For experiment 1, 3 factors (temperature, bleach type, bleach concentration) were evaluated for norbixin destruction using a response surface model-central composite design in liquid whey. For experiment 2, norbixin concentration, residual benzoic acid, and flavor differences were explored in WPC80 from whey bleached by the 2 commercially available BP (soluble and insoluble) at 5 mg/kg. In liquid whey, soluble BP bleached more norbixin than insoluble BP, especially at lower concentrations (5 and 10 mg/kg) at both cold (4°C) and hot (50°C) temperatures. The WPC80 from liquid whey bleached with BP at 50°C had lower norbixin concentration, benzoic acid levels, cardboard flavor, and aldehyde levels than WPC80 from liquid whey bleached with BP at 4°C. Regardless of temperature, soluble BP destroyed more norbixin at lower concentrations than insoluble BP. The WPC80 from soluble-BP-bleached wheys had lower cardboard flavor and lower aldehyde levels than WPC80 from insoluble-BP-bleached whey. This study suggests that new, soluble (liquid) BP can be used at lower concentrations than insoluble BP to achieve equivalent bleaching and that less residual benzoic acid remains in WPC80 powder from liquid whey bleached hot (50°C) than cold (4°C), which may provide opportunities to reduce benzoic acid residues in dried whey ingredients, expanding their marketability., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The lactoperoxidase (LP) system may be used to achieve the desired bleaching of fluid whey with the addition of low concentrations (<50mg/kg) of hydrogen peroxide. The addition of an exogenous peroxidase (EP) to whey may also be used to aid in whey bleaching when the LP system is not fully active. The objectives of this study were to monitor LP activity in previously refrigerated or frozen milk, fluid whey, and whey retentate (10% solids) and to evaluate peroxidase activity in fluid whey and whey retentate (10% solids), with and without additional EP (2, 1, or 0.5 dairy bleaching units), over a range of pH (5.5-6.5) and temperatures (4-60°C). Subsequent experiments were conducted to determine the relationship between enzyme activity and bleaching efficacy. Raw and pasteurized milk, fat-separated pasteurized whey, and whey retentate (10% solids) were evaluated for LP activity following storage at 4 or -20°C, using an established colorimetric method. A response surface model was applied to evaluate both endogenous and EP activity at various temperatures and pH in freshly manufactured whey and retentate. Refrigerated or frozen storage at the parameters evaluated did not affect LP activity in milk, whey, or retentate. In fluid whey, with and without added EP, as pH decreased (to 5.5) and temperature increased (to 60°C), peroxidase activity increased. Retentate with EP exhibited behavior similar to that of fluid whey: as pH decreased and temperature increased, activity increased. However, in retentate without EP, as pH increased and temperature increased, activity increased. Enzyme activity was negatively correlated to bleaching time (time for >80% norbixin destruction) in fluid whey but a linear relationship was not evident in retentate. When fluid whey is bleached enzymatically, if pH is decreased and temperature is increased, the rate of reaction increases (e.g., bleaching occurs in less time). When bleaching in retentate, a higher pH (pH 6.5 vs. pH 5.5) is desired for optimal bleaching by the LP system. Due to processing restraints, this may not be possible for all dairy producers to achieve and, thus, addition of EP could be beneficial to improve bleaching efficacy., (Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The use of whey protein as an ingredient in foods and beverages is increasing, and thus demand for colorless and mild-tasting whey protein is rising. Bleaching is commonly applied to fluid colored cheese whey to decrease color, and different temperatures and bleach concentrations are used. The objectives of this study were to compare the effects of hot and cold bleaching, the point of bleaching (before or after fat separation), and bleaching agent on bleaching efficacy and volatile components of liquid colored and uncolored Cheddar whey. First, Cheddar whey was manufactured, pasteurized, fat-separated, and subjected to one of a number of hot (68°C) or cold (4°C) bleaching applications [hydrogen peroxide (HP) 50 to 500 mg/kg; benzoyl peroxide (BP) 25 to 100 mg/kg] followed by measurement of residual norbixin and color by reflectance. Bleaching agent concentrations were then selected for the second trial. Liquid colored Cheddar whey was manufactured in triplicate and pasteurized. Part of the whey was collected (no separation, NSE) and the rest was subjected to fat separation (FSE). The NSE and FSE wheys were then subdivided and bleaching treatments (BP 50 or 100 mg/kg and HP 250 or 500 mg/kg) at 68°C for 30 min or 4°C for 16 h were applied. Control NSE and FSE with no added bleach were also subjected to each time-temperature combination. Volatile compounds from wheys were evaluated by gas chromatography-mass spectrometry, and norbixin (annatto) was extracted and quantified to compare bleaching efficacy. Proximate analysis, including total solids, protein, and fat contents, was also conducted. Liquid whey subjected to hot bleaching at both concentrations of HP or at 100mg/kg BP had greater lipid oxidation products (aldehydes) compared with unbleached wheys, 50mg/kg BP hot-bleached whey, or cold-bleached wheys. No effect was detected between NSE and FSE liquid Cheddar whey on the relative abundance of volatile lipid oxidation products. Wheys bleached with BP had lower norbixin content compared with wheys bleached with HP. Bleaching efficacy of HP was decreased at 4°C compared with 68°C, whereas that of BP was not affected by temperature. These results suggest that fat separation of liquid Cheddar whey has no effect on bleaching efficacy or lipid oxidation and that hot bleaching may result in increased lipid oxidation in fluid whey., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Reducing the sodium content in cheese is expected to contribute to reducing the overall intake of sodium by US consumers. The purpose of this study was to measure the sodium levels in cheeses that are most commonly purchased by US consumers in the retail market, including brand and private label. A secondary purpose of the study was to generate data that can enable the dairy industry to adopt best practices regarding sodium levels in cheeses. The sodium content of a total of 1,665 samples of Cheddar (650 samples), low moisture part skim (LMPS) Mozzarella (746 samples), and process cheese singles (269 samples) from 4 geographical regions were collected over a period of 3 wk, and were analyzed over a 1-mo period. Process cheese contained the highest mean level of sodium (1,242 mg/100g), followed by string cheese (724 mg/100g). Across Cheddar cheese forms and brands, the mean analytical sodium was 615 mg/100g, with 95% between 474 and 731 mg/100g; label sodium ranged from 600 to 800 mg/100g (mean 648 mg). Across all LMPS Mozzarella forms and brands, the mean analytical sodium was 666 mg/100g, with 95% between 452 and 876 mg/100g; label sodium ranged from 526 to 89 3mg/100g (mean 685 mg). Across all process cheese forms and brands, the mean analytical sodium was 1,242 mg/100g, with 95% between 936 and 1,590 mg/100g; label sodium ranged from 1,185 to 1,740 mg/100g (mean 1,313 mg/100g). These findings demonstrate that manufacturers tended to be conservative with their reporting of sodium on labels. Manufacturers need to reduce variability to better target desired sodium levels, which is an opportunity for better process control, and will enable them to label sodium more accurately., (Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Cheddar cheese is a natural product that has a variable flavor and texture profile. Many companies produce 291-kg blocks of Cheddar cheese, which are subsequently cut and shipped, or stored and subsequently cut. Previous research has shown that compositional differences exist within 291-kg blocks and that these differences may influence flavor and texture development. The objectives of this study were to systematically characterize flavor and texture differences within 291-kg blocks. On 2 different occasions, a 291-kg block was manufactured at each of 4 manufacturing facilities. After 7 d, the 291-kg blocks were sliced into sixteen 18-kg sample portions using a predetermined diagram, and each portion was labeled appropriately (outer corner, inner corner, etc.) and stored at 7 degrees C. Cheese from different locations within the 291-kg blocks was evaluated at 1, 4, 8, and 12 mo. At each time point, two 18-kg portions representing an inside and outside location with the 291-kg block cross-section (from inside to outside) were sampled. The moisture content was lower in the inner than outer locations within the 291-kg blocks. Protein hydrolysis was higher in the inner location and inner locations developed aged Cheddar flavors sulfur, nutty, and brothy more rapidly than the outer locations. However, plant-to-plant differences in aging were often larger than differences caused by block location. These differences were due to differences in cheese manufacturing practices among plants. Dynamic headspace results for flavor volatiles were consistent with descriptive sensory flavor results, documenting differences between inner and outer locations within 291-kg blocks. The inner locations were more fracturable and the outer locations were more cohesive and had more residual in the mouth. Inner locations had greater fracture strain than outer locations. Documenting the differences in aging of 291-kg blocks of Cheddar cheese is important in understanding how to make a consistent high-quality Cheddar cheese.