A catalytic membrane approach as a way to obtain sweet and unsweet lactose-free milk

The growing need in the current market for innovative solutions to obtain lactose-free (L-F) milk is caused by the annual increase in the prevalence of lactose intolerance inside as well as the newborn, children, and adults. Various configurations of enzymes can yield two distinct L-F products: sweet (β-galactosidase) and unsweet (β-galactosidase and glucose oxidase) L-F milk. In addition, the reduction of sweetness through glucose decomposition should be performed in a one-pot mode with catalase to eliminate product inhibition caused by H2O2. Both L-F products enjoy popularity among a rapidly expanding group of consumers. Although enzyme immobilization techniques are well known in industrial processes, new carriers and economic strategies are still being searched. Polymeric carriers, due to the variety of functional groups and non-toxicity, are attractive propositions for individual and co-immobilization of food enzymes. In the presented work, two strategies (with free and immobilized enzymes; β-galactosidase NOLA, glucose oxidase from Aspergillus niger, and catalase from Serratia sp.) for obtaining sweet and unsweet L-F milk under low-temperature conditions were proposed. For free enzymes, achieving the critical assumption, lactose hydrolysis and glucose decomposition occurred after 1 and 4.3 h, respectively. The tested catalytic membranes were created on regenerated cellulose and polyamide. In both cases, the time required for lactose and glucose bioconversion was extended compared to free enzymes. However, these preparations could be reused for up to five (β-galactosidase) and ten cycles (glucose oxidase with catalase).

Milk beverage base with lactose removed with ultrafiltration: Effect of fat and protein concentration on sensory and physical properties

Our objectives were to determine the effect of fat (skim to whole milk) and protein (3.4%-10.5%) concentration on the sensory and physical properties of milk beverage base that had lactose and other low molecular components removed by ultrafiltration (UF). In experiment 1, a matrix of 16 treatments was produced to achieve 4 levels of lactose removal (0%, 30%, 70%, and 97%) at each of 4 fat levels (skim, 1%, 2%, and whole milk). In experiment 2, a matrix of 12 treatments was produced to achieve 4 levels of lactose removal (0%, 30%, 70%, and 97%) at each of 3 protein concentrations (3.4%, 6.5%, and 10.5% protein). Physical and sensory properties of these products were determined. Removal of >95% of milk lactose by UF required a diafiltration volume of approximately 3 times the milk volume. Lactose and low molecular weight solute removal increased whiteness across the range from skim to whole milk while decreasing viscosity and making milk flavor blander. In addition, lactose (and other low molecular weight solute) removal by UF decreased titratable acidity by more than 50% and increased milk pH at 20°C to >7.0. Future work on milk and milk-based beverages with lactose removed by UF needs to focus on interaction of the remaining milk solids with added flavorings, changing casein to whey protein ratio before removal of lactose by UF, and the effect of lactose and low molecular weight solute removal on heat stability, particularly for neutral-pH, shelf-stable milk-based beverages.

Parental perception of children's school lunch milk

School lunch programs are mandated by the US Code of Federal Regulations to serve pasteurized milk that is skim or 1% fat and fortified with vitamins A and D. In recent years, proposals have been made to alter nutritional requirements for school lunches and school lunch milk, including changes to the milk fat and flavor options available. The objective of this study was to evaluate parental understanding and perception of school lunch milk to better understand how changes to school lunch milk are perceived by parents. Four focus groups (n = 34) were conducted with parents of school-aged children (5-13 yr) who purchased milk as part of a lunch at school. Participants were asked about school lunch milk, including nutritional content, packaging, and flavoring. Focus groups included a build-your-own milk activity and discussion of children's milk products currently available on the market. Two subsequent online surveys were conducted with parents of school-aged children (survey 1, n = 216; survey 2, n = 133). Maximum difference scaling was used to evaluate what beverages parents would prefer their child to drink at school (survey 1) and which attributes of chocolate milk for children were most important to parents (survey 2). An adaptive choice-based conjoint activity (survey 1) included flavor, milk fat, heat treatment, label claims, and packaging type. Both surveys included questions to evaluate knowledge of milk nutrition and attitudes regarding milk and flavored milk. Agree/disagree questions were used in both surveys to assess parental opinions of school lunch milk. Survey 2 also included semantic differential (sliding scale) questions to assess parental opinions of chocolate milk and their acceptance of sugar alternatives in chocolate milk served in schools. Parents were familiar with the flavor options and packaging of school lunch milk, but expressed limited familiarity with school lunch milk fat content. Parents perceived milk to be healthy and a good source of vitamin D and calcium. From survey results, parents placed the highest importance on school lunch milk packaging, followed by milk fat percentage and flavoring over label claims and heat treatment. The ideal school lunch milk for parents was unflavored (white milk) or chocolate, 2% fat, and packaged in a cardboard gabletop carton. For school lunch chocolate milk, 3 distinct clusters of parents with differing opinions for children's chocolate milk were identified. Parents are largely unfamiliar with the specific attributes and nutritional profile of milk served in schools but believe that schools should offer milk to their children as part of breakfast and lunch. Parents in both surveys also displayed a preference for 2% fat milk over low-fat options, which provides actionable insight for both governmental bodies determining educational and nutritional policies for school meals and fluid milk producers seeking to optimize their products intended for schools.

Analysis of Eight Types of Plant-based Milk Alternatives from the United States Market for Target Minerals and Trace Elements

A wide variety of commercial plant-based foods that are marketed and sold as alternatives for milk (plant-based milk alternatives or PBMAs) are available to consumers. In this study, PBMAs from the United States (n=85) were subjected to analysis for target minerals (magnesium, phosphorus, selenium, and zinc) to compare their variability across PBMA types, brands, and production lots. Samples were also screened for the environmental contaminant elements arsenic, cadmium, and lead. The eight PBMA types sampled were produced from almond, cashew, coconut, hemp, oat, pea, rice, and soy. Elemental analysis was conducted using microwave-assisted acid digestion followed by inductively coupled plasma-mass spectrometry. The results showed that pea PBMAs contained the highest mean amounts of phosphorus, selenium, and zinc, while soy PBMAs were highest in magnesium. Mean amounts of minerals were lower than those found in milk for the majority of PBMA types. There was significant variation (P<0.05) in amounts of minerals across the majority of product brands. The amounts of phosphorus and magnesium varied across production lots (P<0.05), but the absolute value of these differences was low. Total arsenic was highest in rice PBMAs; amounts of cadmium and lead across PBMAs were generally found at low or non-quantifiable amounts. These results underscore the importance of generating analytical data on the elemental composition of products within the rapidly growing category of PBMA.

Advances in Low-Lactose/Lactose-Free Dairy Products and Their Production

With increasing health awareness worldwide, lactose intolerance has become a major concern of consumers, creating new market opportunities for low-lactose/lactose-free dairy foods. In recent years, through innovating processes and technologies, dairy manufacturers have significantly improved the variety, and functional and sensory qualities of low-lactose and lactose-free dairy products. Based on this, this paper first covers the pathology and epidemiology of lactose intolerance and market trends. Then, we focus on current advantages and disadvantages of different lactose hydrolysis technologies and improvements in these technologies to enhance nutritional value, and functional, sensory, and quality properties of lactose-free dairy products. We found that more and more cutting-edge technologies are being applied to the production of lactose-free dairy products, and that these technologies greatly improve the quality and production efficiency of lactose-free dairy products. Hopefully, our review can provide a theoretical basis for the marketing expansion and consumption guidance for low-lactose/lactose-free dairy products.

Sensory Analysis and Consumer Preference: Best Practices

Sensory science is a multidisciplinary field that encompasses a wide variety of established and newly developed tests to document human responses to stimuli. Sensory tests are not limited to the area of food science but they find wide application within the diverse areas of the food science arena. Sensory tests can be divided into two basic groups: analytical tests and affective tests. Analytical tests are generally product-focused, and affective tests are generally consumer-focused. Selection of the appropriate test is critical for actionable results. This review addresses an overview of sensory tests and best practices.

Cross-sectional determinants of lactose-free food awareness and purchase among adult consumers

This research was conducted to evaluate the knowledge and purchasing behaviour of consumers regarding lactose-free foods. Study data were collected from 1882 individuals with the help of a questionnaire form. Attitudes towards animal welfare, healthy nutrition and gastrointestinal symptoms were also evaluated. The majority (86.6%) of the participants reported that they had heard of the concept of lactose-free foods before, but more than half (67.0%) did not report buying them because of their higher costs compared to regular products and lack of sufficient information. Not causing gas/bloating (32.5%) and being healthier (28.3%) were shown to be the most significant motivational factors in purchasing lactose-free foods (P < 0.05). The factors affecting purchase of lactose-free products were education, employment status, history of having a food intolerance test and animal welfare perception together with higher scores from the gastrointestinal symptom rating scale, and attitude scale for healthy nutrition (P < 0.05). Body mass index was not found to be an effective factor determining purchase intention. The results provide a general overview of consumers, however, further studies on other demographic groups are needed.

Market Basket Survey of the Micronutrients Vitamin A, Vitamin D, Calcium, and Potassium in Eight Types of Commercial Plant-Based Milk Alternatives from United States Markets

We performed a market basket survey of plant-based milk alternatives (PBMAs) from the US market for vitamin A, vitamin D, calcium, and potassium to identify the amount and variability of these micronutrients across various PBMAs. The PBMA types included in this analysis were almond, cashew, coconut, hemp, oat, pea, rice, and soy (n=90 total product units). Analyses for vitamin A (as retinyl palmitate), vitamin D2/D3, and minerals were performed using high-performance liquid chromatography, liquid chromatography-tandem mass spectrometry, and inductively coupled plasma-mass spectrometry, respectively. A majority of PBMA types had significant differences (P<0.05) in the amounts of target micronutrients across brands. The coefficient of variation (%CV) for micronutrient concentrations within one lot of a single brand ranged from 4.1-42.2% for vitamin A, 1.5-44.1% for vitamin D, 1.7%-37.6% for calcium, and 0.7%-39.0% for potassium. The variability of these micronutrients should be taken into account when considering the nutritional value of PBMAs.

Critical Parameters in an Enzymatic Way to Obtain the Unsweet Lactose-Free Milk Using Catalase and Glucose Oxidase Co-Encapsulated into Hydrogel with Chemical Cross-Linking

The presented work involves obtaining and characterising a two-enzymatic one-pot bioreactor, including encapsulated (co-immobilised) glucose oxidase and catalase. The enzymatic capsules were applied to produce unsweet, lactose-free milk during low-temperature catalysis. Furthermore, operational conditions, like pH and aeration, were selected in the paper, which sorts out discrepancies in literature reports. All experiments were carried out at 12 °C, corresponding to milk storage and transportation temperature. Preliminary studies (for reasons of analytical accuracy) were carried out in a buffer (pH, concentration of sugars mimicking conditions in the lactose-free milk, the initial glucose concentration 27.5 g/L) verified by processes carried out in milk in the final stage of the study. The presented results showed the need for regulating pH and the aeration of the reaction mixture in the continuous mode during the process. The procedure of co-immobilisation was performed in an alginate matrix with the cross-linking of glutaraldehyde or carbodiimide while carbodiimide showed better enzymes retention inside alginate capsules. Co-encapsulated enzymes could be used for nine cycles, preserving finally about 40% of the initial activity.

Evolution of Milk Consumption and Its Psychological Determinants: A Mini-Review

The consumption of lactose-free products and in particular lactose-free milk is increasing worldwide. Although many studies claim that this dietary trend is mainly determined by the number of lactose intolerant people that is growing, others state that most of them self-report an intolerance that has not been diagnosed by medical tests. However, many researchers reported that the consumption of lactose-free milk may put the consumers' health at risk especially when the subjects are not intolerant. Consequently, understanding this new dietary trend considering its main determinants it is necessary to generate educational and intervention campaigns useful to guide people toward healthier and more adequate eating styles. For these reasons we conducted a narrative mini review to summarize the factors contributing to the consumption of lactose-free milk as an alternative to cow's milk, exploring intrinsic and extrinsic product characteristics, biological and physiological, as well as psychological, situational and socio-cultural factors. This narrative mini-review shows that there are six categories of factors that affect the consumption of lactose-free milk. In particular, the intrinsic aspects linked to the product and the socio-demographic characteristics of the consumer are the most explored. On the contrary, situational and socio-cultural factors are the least studied. Finally, this study argues that there are too few studies that investigates the emotional, identity and social aspects underlying these food choices, suggesting the development of future research that investigate the implicit consumer subjective levers to decipher lactose-free milk consumptions.

Consumer perception of natural hot-pepper cheeses

Hot-pepper cheese (HPC) is a growing category of flavored natural cheese. The objective of this study was to evaluate consumer perception of HPC using a combination of quantitative survey methods and consumer evaluation of HPC. An online survey (n = 510) was conducted to understand drivers of purchase for the HPC category. Consumers of HPC answered maximum difference exercises and an adaptive choice-based conjoint activity focused on HPC attributes. Subsequently, natural HPC were manufactured in duplicate with 5 different hot-pepper blends with a range of heat intensities and distinct color differences. Trained panel profiling and consumer-acceptance testing (n = 194 consumers) were conducted on the cheeses. Three clusters of consumers were identified from the online survey. Cluster 1 (n = 175) were traditional HPC consumers, and cluster 2 (n = 152) preferred milder HPC. Cluster 3 (n = 183) showed preference for spicier HPC as well as novel HPC, such as those made with habanero peppers or white Cheddar cheese. Conceptually, the overall ideal HPC was a Monterey Jack with medium-sized, multicolored pieces of jalapeno peppers and a medium heat and spiciness. Heat and spiciness intensity and type of cheese were the most important attributes. The 5 HPC used in consumer testing had a distinct range (low to high) of hot-pepper burn and heat intensity by trained panel profiling. Consumer overall liking increased as hot-pepper burn and heat intensity increased to a certain point, indicating HPC consumers may have an optimal point for heat and spiciness in HPC. Consumers also preferred HPC with multicolored pepper pieces over those with a single pepper color, consistent with survey results. Consumers who self-reported that they prefer mild- or medium-spicy foods (mild consumers) preferred HPC that were less intense in hot-pepper burn than consumers who self-reported preference for hot or spicy foods (hot consumers). Most HPC consumers preferred HPC with higher heat intensity and were also motivated by visual characteristics of HPC.

Consumer perception of ice cream and frozen desserts in the "better-for-you" category

The consumption of ice cream and frozen desserts in the "better-for-you" (BFY) category has grown rapidly over the past few years, even as traditional ice cream sales remain stagnant. To better understand consumer preferences within the BFY category, an online survey (n = 1,051) was conducted with ice cream and frozen dessert consumers, followed by consumer acceptance testing of commercial BFY frozen dairy desserts. Consumers of BFY frozen desserts (n = 578) completed an adaptive choice-based conjoint survey and MaxDiff exercise to identify the attributes that drive purchase of BFY frozen desserts. MaxDiff exercises were also used to determine which attributes all frozen dessert consumers (n = 1,051) perceived to make a frozen dessert BFY and which stabilizers or emulsifiers were most attractive on an ice cream or frozen dessert label. Subsequently, a consumer acceptance test (n = 186) was conducted using 4 commercial vanilla-flavored frozen dairy desserts made with different sweetening systems (sugar, sucralose + acesulfame K, monk fruit + allulose, and stevia + erythritol). Half of consumers were primed or informed with the sweeteners and basic nutritional information for the frozen desserts before tasting, and the other half of consumers evaluated samples blinded, where they were only informed that they were tasting a vanilla-flavored frozen dessert. Sweetener type and base (dairy vs. plant) were the most important attributes to BFY consumers when selecting a BFY frozen dessert (n = 578). For all ice cream and BFY dessert consumers (n = 1,051), sweetener-related claims (naturally sweetened, reduced sugar, no added sugar), along with "all natural" and a short ingredient list, were the top attributes that contributed to perception of a "healthier" frozen dessert. When BFY frozen desserts were tasted by consumers, purchase intent decreased after tasting, suggesting that frozen desserts made with natural non-nutritive sweeteners did not meet consumer expectations. Flavor of BFY frozen desserts remains more important than perceived healthiness. Consumers perceive frozen desserts, even those in the BFY category, as an indulgence. Frozen dessert manufacturers should focus on naturally sweetened, dairy-based desserts with minimal sweetener-related flavor defects when designing products for the BFY category.

Consumer understanding of fluid milk and cheese processing and composition

Ultrafiltration and microfiltration are 2 types of membrane filtration commonly used by the dairy industry. Filtered milk products are becoming increasingly common, but there is concern that consumers unfamiliar with these processing methods may form negative uninformed perceptions of cheeses made with these milks. There are many studies that address the chemical and physical properties of cheeses made with filtered milk, but, to our knowledge, there are none that address consumer perception of these products. Similarly, ultrapasteurization is becoming more common for US dairy products. Although previous work has characterized consumer liking of ultrapasteurized milks, few have investigated understanding and perception of this process. The objective of this study was to explore consumer understanding of milk processing and constituents, particularly as it relates to milk used as an ingredient in cheese. To achieve this goal, we investigated the following 4 questions: (1) Does the average dairy product consumer understand the basic ingredients and nutrients in fluid milk and cultured dairy products? (2) Does the average dairy product consumer understand the basic processes for fluid milk and cultured dairy products? (3) Do different processes affect consumer perception or purchase intent? (4) Does explaining a process change consumer understanding of, beliefs about, and purchase intent for dairy products? Qualitative interviews (n = 54) and an online survey (n = 1,210) were conducted with dairy product consumers. Survey responses paralleled those from one-on-one interviews. The average dairy product consumer could recall key words related to dairy processing, composition, nutrients, and ingredients, but was largely unfamiliar with these subjects. Highly educated and older consumers were more likely to have a better understanding of dairy composition and nutrition, particularly lactose content of milk and Cheddar cheese and the source of fluid whey and whey protein. Processing-related descriptors (e.g., ultrapasteurized or ultrafiltered) in ingredient statements were likely to be overlooked on labels (especially for familiar products), as just 34% of dairy product consumers read the labels on dairy products often or always before purchase. The majority (>80%) of dairy product consumers were unfamiliar with ultrafiltered or microfiltered milk, but uninformed perceptions were generally positive. Consumers unfamiliar with processing methods were likely to assume those methods increase the price of a dairy product. For the majority of consumers, purchase intent for fluid milk and cultured dairy products was not affected when nonconventional processing terms such as ultrafiltered or microfiltered were included in the ingredients statement. This effect was consistent for fluid milk and Cheddar cheeses but not for cottage cheese, suggesting the possibility of product-specific effects. Providing respondents with a definition of filtration increased consumer understanding of, positive beliefs about, and purchase intent for fluid filtered milk and cheese made with filtered milk. Educating consumers through on-package labeling and other marketing messaging should be investigated for dairy products that incorporate processes such as ultrapasteurization or filtration.

A New Food Composition Database of Lactose-Free Products Commercialized in Spain: Differences in Nutritional Composition as Compared to Traditional Products

We developed a new database to evaluate the nutritional composition of lactose-free products from Spain. The database includes dairy products and other products, all of which show the "lactose-free" declaration on their label, accounting for 327 products in total. Of these, 123 are dairy products, 16 are non-dairy products which include a dairy ingredient (5%) and 188 items (57% of the sample) are non-dairy products that do not contain any dairy ingredient. The main subgroups are yogurt (25%), milk (24%), and cheese (17%). Nineteen percent of the compiled products included nutritional claims on their labels. Most lactose-free products did not contain either added sugars or low- or no-calorie sweeteners (58%), while 34% included added sugars and only 6%, sweeteners or a combination of both (2%). We found that 19.5%, mainly within the milk subgroup, were fortified with vitamins A, D, E, K, B₉, and B₁₂, P, and Ca. There were no significant differences in the nutritional composition between lactose-free products and traditional products. According to the NOVA classification, 55% of compiled lactose-free products were ultra-processed, and 20% processed. The array of lactose-free products marketed in Spain proves that there are enough, both in quantity and quality, to satisfy the dairy needs of lactose intolerants.

The influence of automatic associations on preference for milk type

In recent decades, organic milk has been an exception to the trend of decreased fluid milk consumption in the United States. However, the reasons behind consumer preference for organic milk over conventional and other milk types are ill-defined. The objective of this study was to use an implicit association test (IAT) and primed and unprimed preference testing to determine if fluid milk consumer preferences for milk types are influenced by implicit biases and, if so, to define these biases within the context of the consumer sensory experience. Self-reported fluid milk consumers (n = 473) participated in online IAT exercises where pairwise comparisons of milk types (conventional, organic, local, pasture-raised) were measured on both positive and negative dimensions related to cow-welfare, sustainability, health, trust, safety, and quality. Latency times from IAT responses were subsequently transformed into standardized D-scores to categorize bias effect sizes. Additionally, fluid milk consumers (n = 174) participated in preference tests that compared commercial milks representing different milk types through presentations where milk type was shown (primed) or hidden (unprimed). Following preference tests, consumers were asked to explain their preferred sample using check-all-that-apply tasks. Analysis of IAT results showed that conventional milk was more associated with negative dimension descriptors compared with organic, local, and pasture-raised milks. Additionally, a positive bias in favor of organic milk was expressed when compared with pasture-raised milk offerings; however, no differences were found in pairwise comparisons of other nonconventional milk type pairings, suggesting that consumers may conflate these designations. Blinded preference testing showed that milk preferences were largely dictated by flavor, with consumers differentiating milk types based upon flavors related to packaging, pasteurization method, and feeding systems. In primed evaluations, consumers generally expressed preferences that aligned with their explicit beliefs, and flavor considerations appeared to be a secondary differentiator of preference. Based on these results, conventional milk is associated with negative implicit beliefs related to production and product quality more often than other milk types, which was reflected in IAT evaluations and primed preference tests. However, the blinded tastings suggested that conventional milk was preferred, or competitive with, other milk types based on flavor alone. Findings from this study suggest consumer differentiation and preference of milks is significantly affected by perceptions and beliefs related to milk type. In particular, conventional milk was associated with relatively few unique belief descriptions, indicating strict utilitarian consumer categorization. Organic and local milks were comparatively associated with greater care for nutrition, sustainability, animal welfare, and local farm support. These results demonstrate a need for greater education related to conventional milk offerings to dispel factors influencing negative implicit bias. Furthermore, improving product narrative via label information and alignment with locality and regionality were identified as possible opportunities for improving consumer sentiments related to conventional milk. A more thorough understanding of these attributes may reinforce stated beliefs more effectively and stave off consumer losses to plant-based alternatives that fulfill similar beliefs.

Energy and Nutrient Intake of Americans according to Meeting Current Dairy Recommendations

Most Americans do not meet dairy food recommendations from the 2015 Dietary Guidelines for Americans (DGA). This study assesses differences in nutrient intake between Americans who meet recommendations for dairy intake and those who do not, using data from the National Health and Nutrition Examination Survey from 2013–2014 and 2015–2016 (n = 5670 children ages 2–18 years and n = 10,112 adults ages 19+). Among children and adults, those meeting dairy food recommendations were significantly more likely to have adequate intake (% above Estimated Average Requirement (EAR)) of calcium, magnesium, phosphorus, riboflavin, vitamin A, vitamin B12, and zinc and consume above the Adequate Intake (AI) for potassium and choline than Americans not meeting dairy recommendations, regardless of age, sex, or race/ethnicity. Americans meeting dairy recommendations were also more likely to exceed recommendations for sodium and saturated fat but consume less added sugars. Nearly 60% of Americans 2 years and older not meeting dairy recommendations consumed calcium and magnesium below the EAR. Only about 20% of Americans who did not meet dairy recommendations consumed above the AI for potassium. Dairy foods make important and unique contributions to dietary patterns, and it can be difficult to meet nutrient needs without consuming recommended amounts of dairy foods.