Lactose-free Dairy Research Articles

Development of low-lactose curd product with papaya

Today, low-lactose (LL) and lactose-free (LF) dairy products have widespread health benefits throughout the world. To obtain LL and LF of curd products, the modern market of LL and LF products was studied, based on the analysis of which the composition of raw materials and methods for obtaining LL of a curd product were substantiated using the example of LL curd paste with papaya puree. The process of lactose hydrolysis was studied and the optimal modes of its hydrolysis were determined. The development of LL curd products with papaya will help reduce vitamin A deficiency and protein-energy malnutrition (PEM) in the population in Vietnam. The new product will expand the range of functional foods, increase the consumption of fermented milk products among the population of all ages, provide the body with many important nutrients, and strengthen the immune system.

Strategies to determine lactose in cow milk by mid infrared spectroscopy

The lactose-free dairy sector has been growing considerably, requiring rapid and accurate methodologies for lactose determination. The present work aimed to explore spectroscopy and statistic strategies to estimate the lactose content in cow milk using mid infrared spectroscopy (MIRS) and chemometric tools. Firstly, regular and lactose-free milk discrimination was successfully performed using the spectral range of 935−1200 cm−1 along with Partial Least Squares Discriminant Analysis (PLS-DA). Secondly, to estimate the percentage of lactose in lactose-free milk, calibration models were developed by Partial Least Squares (PLS), Multiple Linear Regression (MLR), and Least Squares Regression (MQ) with and without spectral transformation. The three methods proved to be efficient, with the best performance obtained by the PLS model using Multiplicative Scatter Correction from 935 to 1200 cm−1, with low RMSE values and R2 > 0.99 for calibration, cross and external validation. Furthermore, high-performance liquid chromatography (HPLC) was used to attest the good predictive ability of lactose content in lactose-free milk by MIRS-PLS. Finally, the models were used to monitor the lactose content during the enzymatic hydrolysis, showing the applicability and efficiency of the proposed method. Therefore, MIRS associated with chemometric tools constitutes a method with a high capacity to discriminate between regular and lactose-free milk, as well as to predict lactose content in both milk samples.

Technological and methodological aspects of the production of low- and lactose-free dairy products

The features of technologies for low- and lactose-free dairy products, which provide for special operations to hydrolyze lactose or remove it using ultra- or nanofiltration followed by hydrolysis of the residual amount, are considered. Dairy products manufactured using these technologies in different countries as well as enterprises leading in this field of production are presented. The analysis of the methods used to determine the quantitative content of residual lactose in low- and lactose-free dairy products is carried out: enzymatic, HPLC, HPAEC-PAD, amperometric biosensors, Raman spectroscopy. Due to the dairy industry’s need for analytical methods for the determination of lactose in milk and dairy products with low- or lactose-free content, the AOAC Stakeholder Group on Strategic Food Analysis Methods approved Standard Performance Requirements for Biosensor Methods (SMPR®) 2018.009. These requirements were introduced for the quantitative determination of lactose in milk as well as in dairy and milk-containing products with a low or no lactose content. The biosensor method is recommended for use as the official first step of AOAC method. Additionally, it is advisable to use high performance liquid chromatography (HPLC) with mass spectrometric detection, as well as high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) as an international standard method of analysis for the determination of lactose in milk with low- or lactose-free content.

Current knowledge about physical properties of innovative probiotic spray-dried powders produced with lactose-free milk and prebiotics

Lactose-free probiotic powders were obtained by mixing Bifidobacterium BB-12 suspensions with lactose-free milk powder or lactose-free milk powder and prebiotics (inulin or oligofructose). A thorough investigation was performed to know their water sorption properties and physical and thermal characteristics. By evaluating the water sorption properties, the Peleg model fitted well to the experimental sorption data, showing that the equilibrium moisture content of powders increased as the relative humidity increased. The isotherm found for all samples was a Type III Isotherm, commonly observed in most foods. For both morphology and particle size, the use of different carrier agents affected these properties; however, all the spray-dried powders presented good size to be added in food products. X-ray diffraction and Raman spectroscopy showed us amorphous structure for all powders, and typical bands of the milk constituents and sugars, respectively. Regarding the spray-dried powders thermal properties, it was possible to confirm that the addition of prebiotics gave higher thermal stability, highlighting the sample produced with inulin. We concluded that a good quality of lactose-free milk based probiotic powder could be obtained using spray drying technique, with great potential to be applied in lactose-free dairy products.

Additional costs of lactose-reduced diets: lactose-free dairy product substitutes are a cost-effective alternative for people with lactose intolerance.

People with lactose intolerance have to limit their consumption of lactose-containing dairy products which are a main source of Ca. In particular, for low-income people it is of interest which alternative diet form rich in Ca leads to the lowest additional costs. This study aims to calculate the additional costs of lactose-reduced diets and to show which of different options represent the most cost-effective alternative within a lactose-reduced diet. Using linear programming, food baskets with different lactose contents were calculated and were compared to a basic model, reflecting a normal diet without a limitation of lactose. By comparing the costs and the composition of the food baskets, recommendations for a lactose-reduced diet were derived. Germany. A consumer panel dataset representative for Germany is used for the calculations. Information on prices and nutrients is derived from the 9429 adult households without children, and information on consumed food quantities from the 3046 single households. The minimum additional food costs depend on the severity of lactose intolerance and range from 0·2 % to 6·1 % per month. It was found that the greatest adjustments due to lactose reduction could be observed within the dairy product group. In this group, with a rising lactose limit, normal milk was increasingly replaced by lactose-free milk. It was shown that a lactose-reduced diet is generally associated with higher food costs. When suffering from lactose intolerance, switching to lactose-free milk seems to be the most cost-effective way to cover nutrient requirements.

FORMATION OF THE DOMESTIC MARKET OF LACTOSE-FREE AND LOW-LACTOSE DAIRY PRODUCTS

Background. The problem of lactose intolerance is becoming widespread, especially in Ukraine it affects 15–35 % of the population. Dairy products are a valuable source of essential nutrients, that’s why it is impossible to completely rule out them from the diet. To solve this problem, it is important to develop technology for dairy products that are free of lactose or with reduced content. The aim of thework is to analyze the world market of low-lactose dairy products and to identify the factors which influence on the formation of such a market in Ukraine. Materials and methods. The subject of the study is the market segment of lactose-free and low-lactose dairy products. Methods of analysis and synthesis, statistical methods of evaluation, scientific generalization and comparison of data are used. Results. The formation of a healthy food market is characterized by gro­wing demand for special food products with regulated nutrient composition, in particular for dairy products, lactose-free or with its reduced content. However, in Ukraine, this market is still in its infancy. Today in country there are 160 units of lactose-free and low-lactose dairy pro­ducts. The volume of imported products in the general range is 68.13%. Kefir and sour cream have the largest share in the formation of the domestic market of low- and lactose-free dairy products, and domestic yogurts have the smallest part. Therefore, the saturation of the market with domestic yogurt, free of lactose, or with its reduced content, is an important area of the development of the Ukraine’s dairy industry. The restriction of natural food resources negatively affects the formation of the domestic market of low-lactose dairy products. In 2020, milk production decreased by about 7 %, due to the unstable economic situation caused by quarantine restrictions in the context of the COVID-19 pandemic. That’s why today the problem of complete collection and rational use of secondary raw milk in the production of food products dominates., especially dairy products of the "free-from" category. Conclusion. The need to create new technologies for low-lactose dairy products using local bioavailable raw materials is essentially due to their high demand and a narrow range of domestic products. The priority directions of development of the domestic market of low-lactose and lac­tose-free dairy products are offered in the context of the state policy of introduction of resource-saving and increase of volumes of high-quality production of domestic production.

Purified lactases versus whole-cell lactases-the winner takes it all.

Lactose-free dairy products are in great demand worldwide due to the high prevalence of lactose intolerance. To make lactose-free dairy products, commercially available β-galactosidase enzymes, also termed lactases, are used to break down lactose to its constituent monosaccharides, glucose and galactose. In this mini-review, the characteristics of lactase enzymes, their origin, and ways of use are discussed in light of their potential for hydrolyzing lactose. We also discuss whole-cell lactase catalysts, which appear to have great potential in terms of cost reduction and convenience, and which are more natural alternatives to purified enzymes. Lactic acid bacteria (LAB) already used in food fermentations seem to be optimal candidates for whole-cell lactases. However, they have not been industrially exploited yet due to technical hurdles. For whole-cell lactases to be efficient, the lactase enzymes inside the cells must be made available for lactose hydrolysis, and thus, cells need to be permeabilized or disrupted prior to use. Here we review state-of-the-art approaches for disrupting or permeabilizing microorganisms. Lastly, based on recent scientific achievements, we propose a novel, resource-efficient, and low-cost scenario for achieving lactose hydrolysis at a dairy plant using a LAB whole-cell lactase.Key points• Lactases (β-galactosidase) are essential for producing lactose-free dairy products• Novel permeabilization techniques facilitate the use of LAB lactases• Whole-cell lactase catalysts have great potential for reducing costs and resources Graphical abstract.

Determination of Carbohydrates in Lactose-Free Dairy Products to Support Food Labelling

Milk and its derivatives are the basis of human nutrition since childhood. Given their importance within a balanced diet, the determination of carbohydrates in milk and its derivatives is fundamental for two reasons: one of alimentary origin related to intolerances and the other one of technological origin, especially for PDO (Protected Designation of Origin) products. The dietetic approach, including lactose-free products, has a crucial role in the management of lactose intolerance, but labelling and compositional rules indicating the absence or reduced presence of lactose in food are currently not harmonised at Union level. Considering the above-mentioned issues and the absence of official methods for the determination of low sugar concentrations, we propose a new and simple IC-HRMS method to detect carbohydrates in milk and different lactose-free derivatives, which can allow the definition of concentration limits useful to characterise products suitable for specific dietary regimes.

Immobilization of β-galactosidase from Bacillus licheniformis for application in the dairy industry.

The food industry has developed a wide range of products with reduced lactose to allow people with intolerance to consume dairy products. Although β-galactosidase has extensive applications in the food, pharma, and biotechnology industries, the enzymes are high-cost catalysts, and their use makes the process costly. Immobilization is a viable strategy for enzyme retention inside a reactor, allowing its reuse and application in continuous processes. Here, we studied the immobilization of β-galactosidase from Bacillus licheniformis in ion exchange resin. A central composite rotational design (CCRD) was proposed to evaluate the immobilization process in relation to three immobilization solution variables: offered enzyme activity, ionic strength, and pH. The conditions that maximized the response were offered enzyme activity of 953 U, 40 mM ionic strength, and pH 4.0. Subsequently, experiments were performed to provide additional stabilization for biocatalyst, using a buffer solution pH 9.0 at 25 °C for 24 h, and crosslinking with different concentrations of glutaraldehyde. The stabilization step drastically impacted the activity of the immobilized enzyme, and the reticulation with different concentrations of glutaraldehyde showed significant influence on the activity of the immobilized enzyme. In spite of substantially affecting the initial activity of the immobilized enzyme, higher reagent concentrations (3.5 g L-1) were effective for maintaining stability related to the number of cycles of the enzyme immobilized. The β-galactosidase from Bacillus licheniformis immobilized in Duolite A568 is a promising technique to produce reduced or lactose-free dairy products, as it allows reuse of the biocatalyst, decreasing operational costs.Key Points• Immobilization of β-galactosidase from Bacillus licheniformis in batch reactor• Influence of buffer pH and ionic concentration and offered enzyme activity on immobilization• Influence of glutaraldehyde on operational stability.

Analysis of the target group of lactose-free functional foods for product development

Abstract The aim of this research was to assess the consumer habits of lactose sensitive persons in case of lactose-free products and their other shopping aspects for development of new, dairy-based lactose-free products. The research was based on face-to-face questionnaire survey, and those who declared to be lactose sensitive were analysed. Among them, only half of the women (49.3%) and one third of the men (34.6%) were medically proven lactose sensitive, so more than half of the respondents declared themselves affected on the basis of self-diagnosis. Our results show that reliably regular customers of lactose-free products are women and persons with medical diagnosis, high educational degree, and under the age of 30. The lactose-free consumer group prefers the following product features: lactose-free label; rich in calcium, vitamins, and fibre, and free of carbohydrate, sugar, and gluten. Only two-thirds of lactose sensitive customers (66.7%) consume lactose-free products regularly, so it can be assumed that the level of knowledge of this disease, its treatment, and the importance of lactose-free dairy products among these persons is insufficient. This could be solved with education, advertisement, and other information opportunities.

Determination of lactose in low-lactose and lactose-free dairy products using LC-MS

An LC–MS method was developed for routine determination of lactose in low-lactose and lactose-free dairy products. The lactose was separated on an amide column under an isocratic elution condition. Baseline separation of lactose from common interferents, including epilactose, lactulose, and allolactose were achieved under this LC conditions. The lactose chloride-35 adduct ions were detected by a single quadrupole MS in ESI- mode. 13C labeled lactose was used as an internal standard. The LOQ was estimated at 2.6 mg/100 g in a soy based infant formula. The recovery was found within the range of 90%–109% in the spiking study on commercial dairy products at spiking levels between 3.4 and 461 mg/100 g. The analysis of lactose concentration in the NIST SRM 1849a showed an accuracy of 109%. The RSD in the analysis of those commercial products were less than 4.3%. This method is sensitive and selective enough and fit for the routine determination of lactose in low-lactose and lactose-free dairy products.

Stabilization of β-Galactosidase on Modified Gold Nanoparticles: A Preliminary Biochemical Study to Obtain Lactose-Free Dairy Products for Lactose-Intolerant Individuals.

The unique chemical, optical, and electrical characteristics of nanoparticles make their utilization highly successful in every field of biological sciences as compared to their bulk counterpart. These properties arise as a result of their miniature size, which provides them an excellent surface area-to-volume ratio, inner structure, and shape, and hence increases their surface characteristics. Therefore, this study was undertaken to engineer gold nanoparticles (AuNPs) for improving their catalytic activity and stability in biotechnological processes. The characterization of AuNPs was performed by XRD, UV spectra, and TEM. The synthesized AuNPs were surface-modified by polyvinyl alcohol (PVA) for binding the enzyme in excellent yield. The developed immobilized enzyme system (PVA-AuNPs-β-galactosidase) displayed pH optima at pH 7.0 and temperature optima at 40 °C. Moreover, the stability of PVA-AuNPs-β-galactosidase was significantly enhanced at wider pH and temperature ranges and at higher galactose concentrations, in contrast to the free enzyme. β-galactosidase bound to PVA-modified AuNPs exhibited greater operational activity, even after its sixth reuse. The developed nanosystem may prove useful in producing lactose-free dairy products for lactose-intolerant patients.

Cold-Active β-Galactosidases: Insight into Cold Adaption Mechanisms and Biotechnological Exploitation.

β-galactosidases (EC 3.2.1.23) catalyze the hydrolysis of β-galactosidic bonds in oligosaccharides and, under certain conditions, transfer a sugar moiety from a glycosyl donor to an acceptor. Cold-active β-galactosidases are identified in microorganisms endemic to permanently low-temperature environments. While mesophilic β-galactosidases are broadly studied and employed for biotechnological purposes, the cold-active enzymes are still scarcely explored, although they may prove very useful in biotechnological processes at low temperature. This review covers several issues related to cold-active β-galactosidases, including their classification, structure and molecular mechanisms of cold adaptation. Moreover, their applications are discussed, focusing on the production of lactose-free dairy products as well as on the valorization of cheese whey and the synthesis of glycosyl building blocks for the food, cosmetic and pharmaceutical industries.

Effect of Temperature, pH and Amount of Enzyme Used in the Lactose Hydrolysis of Milk

Lactose intolerance is becoming a health state that requires the restriction of dairy products in the diet of people suffering from this condition. But milk and dairy products, due to a well-balanced composition in the main macro and micronutrients, cannot be missing from the diet of the consumer of any age. For these reasons, in recent years, in the milk processing industry, the production of low-lactose or lactose-free dairy products is explored. To reduce the lactose content of dairy raw materials, various industrial and biotechnological methods were used: enzymatic hydrolysis of lactose, baromembranous methods, bioconversion of lactose by lactic bacteria and others. The most widely used lactase enzymes in the industry are mesophilic enzymes from filamentous fungi (Aspergillus spp.) and yeasts (Kluyveromyces spp.). Therefore, the aim of this study was to evaluate the effect of the commercial enzyme β-galactosidase on the hydrolysis of cow’s milk at different enzyme concentrations, temperatures and pH. Two commercial enzymes β-galactosidase obtained from Bacillus licheniformis and β-galactosidase obtained from Kluyveromyces lactis, were used in this study, according to information provided by the manufacturer. The thermal stability of lactose, the effect of milk pH, the effect of temperature, duration of hydrolysis and the amount of enzymes on the lactose hydrolysis degree and the sweetness degree of milk were determined. Research has identified the optimal parameters for obtaining a high degree of lactose hydrolysis in the use of these enzymes. Therefore, to ensure a high lactose hydrolysis degree (over 80%), the following lactose hydrolysis regimens were identified: temperature 4&degC - 6&degC, 0.3% Bacillus licheniformis enzymes, duration 4 hours; temperature 4&degC - 6&degC, 0.3% enzymes from Klavyromyces lactis, duration 12 hours and temperature 38&degC - 40&degC, 0.15% enzymes from (Bacillus licheniformis or Klavyromyces lactis), duration 2 - 3 hours. The results obtained allow the efficient use of Bacillus licheniformis and Klavyromyces lactis enzymes in industrial processes for the manufacture of “lactose-free” or “low-lactose” drinking milk and fermented dairy products for people with lactose intolerance.

Changes in the stability of ultra-pasteurized lactose-free milk upon storage

Lactose-free dairy products are a valued consumer option for lactose intolerant individuals. Short-term ultra-high pasteurization (UHT) allows the preparation of sterile milk products. Manufactures define the useful shelf life of UHT milk as 120 days. This study analyses lactose-free milk with low-fat content over 120 days of shelf storage. Milk composition, microbial presence, structure (micellar size and zeta potential), color, pH, and protein hydrolysis were examined. At 120 days of storage the pH decrease, change in particle size distribution, and significant browning of the milk were detected indicating meaningful changes in the milk structure. The changes occurring in the lactose-free milk are related to the introduction of a large number of reducing sugars as a result of delactosylation of the milk. Studied milk had no microbial contamination nor showed the presence of by-products contamination such as proteases (minimal hydrolysis after long time storage).

A Cluster Project Approach to Develop New Functional Dairy Products from Sheep and Goat Milk

The growing scientific interest in the role of food in promoting human health and wellbeing has profoundly influenced consumers’ perceptions and attitudes towards nutrition, leading to the advent of a new class of foods, called functional foods, which are currently one of the fastest growing food-producing sectors, particularly in the dairy industry. The cluster project “Diversification in sheep & goat Sardinian dairy production” was built and carried out, based on requests from ten Sardinian dairy companies, to plan and implement experimental protocols directed to develop new production processes, according to the latest health and nutritional guidelines. Consequently, the following different interconnected research lines were developed: lactose-free dairy products; low-fat dairy products; dairy products enriched with added functional ingredients. The studied processes were based on the modification of cheese milk or whey, through the elimination of or reduction in one or more components with negative health effects or by adding functional ingredients. Therefore, a total of six different dairy products were developed: two from sheep milk and whey and four from goat milk. The technological processes adopted were typically those of Ricotta, fresh and soft cheeses. Contextually, their adaptability to the industrial equipment available in the cluster dairy companies was verified, and most of them were successfully transferred. These novel dairy products meet the current market demand, which shows a greater interest in fresh and short-ripened dairy products, with a low energy intake and high nutritional value. Moreover, can represent an example of the diversification in the sheep and goat dairy sector.

Effects of enzymatic lactose hydrolysis on thermal markers in lactose-free UHT milk.

Lactose-free products are more susceptible to chemical and physical modifications during heating and storage, due to the release of glucose and galactose during enzymatic processing, both more reactive than lactose. The present study demonstrates the effect of enzymatic lactose hydrolysis on 5-hydroxymethylfurfural (HMF), whey protein nitrogen index (WPNI) and lactulose used as thermal markers for UHT milk process monitoring. Six milk leading brands which provided regular and lactose-free UHT milk were selected, giving a total of 12 UHT milk samples analyzed in authentic duplicates. All lactose-free samples showed high levels of HMF index (42.15µmol L-1, against 13.11µmol L-1 for regular samples) and low lactulose contents (13.03mg 100mL-1, against 35.59mg 100mL-1 of regular ones). High variations in HMF (55-85%) and lactulose (42-91%) intra-brand analysis indicated that both markers are influenced by the lactose hydrolysis process. The paired t test indicated there was no difference among WPNI indexes of regular and lactose-free milks suggesting that this thermal marker is suitable to infer about heat damage in lactose-free dairy matrices.

No more cleaning up -Efficient lactic acid bacteria cell catalysts as a cost-efficient alternative to purified lactase enzymes.

β-galactosidases, commonly referred to as lactases, are used for producing lactose-free dairy products. Lactases are usually purified from microbial sources, which is a costly process. Here, we explored the potential that lies in using whole cells of a food-grade dairy lactic acid bacterium, Streptococcus thermophilus, as a substitute for purified lactase. We found that S. thermophilus cells, when treated with the antimicrobial peptide nisin, were able to hydrolyze lactose efficiently. The rate of hydrolysis increased with temperature; however, above 50°C, stability was compromised. Different S. thermophilus strains were tested, and the best candidate was able to hydrolyze 80% of the lactose in a 50g/L solution in 4h at 50°C, using only 0.1g/L cells (dry weight basis). We demonstrated that it was possible to grow the cell catalyst on dairy waste, and furthermore, that a cell-free supernatant of a culture of a nisin-producing Lactococcus lactis strain could be used instead of purified nisin, which reduced cost of use significantly. Finally, we tested the cell catalysts in milk, where lactose also was efficiently hydrolyzed. The method presented is natural and low-cost, and allows for production of clean-label and lactose-free dairy products without using commercial enzymes from recombinant microorganisms. KEY POINTS: • Nisin-permeabilized Streptococcus thermophilus cells can hydrolyze lactose efficiently. • A low-cost and more sustainable alternative to purified lactase enzymes. • Reduction of overall sugar content. • Clean-label production of lactose-free dairy products.

유당불내증에 효과적인 유당이 없는 낙농 유제품의 개발: 현재와 미래

Lactose intolerance is a pathophysiological phenomenon caused by a deficiency of the enzyme lactase present in human intestines. Changes in intestinal digestion and colon fermentation after the intake of lactose-containing products cause diarrhea and other clinical discomforts. Therefore, lactose intolerance can be easily ameliorated by consuming lactose hydrolyzed milk and dairy products. In the recent years, lactose-free dairy products have provided lactose intolerant consumers with several options, due to an improvement in the quality and an increase in the variety of products. Currently, the manufacturing of lactose-free products also represents the fastest growing sector in the dairy industry. This review, thus, aims to provide an overview of the current availability and prospects of lactose-free dairy products, and also discuss the potential benefits of the development of a variety of lactose-free dairy foods.

Application of PTR-TOF-MS for the quality assessment of lactose-free milk: Effect of storage time and employment of different lactase preparations.

Lactose-free dairy products undergo several chemical modifications during shelf life because of the reactivity of glucose and galactose produced by the lactose enzymatic hydrolysis. In this study, proton transfer reaction-mass spectrometry (PTR-MS), coupled with a time-of-flight (TOF) mass analyzer, was applied to get an insight on the phenomena occurring during the shelf life of ultrahigh-temperature (UHT) lactose-free milk (LFM). UHT LFMs produced by three different commercial lactase preparations were evaluated during storage at 20°C over a 150 days period, sampling the milk every 30 days. Production was repeated three times, on three consecutive weeks, in order to take milk variability into consideration. Principal component analysis applied to the whole "volatilome" data demonstrated the capability of PTR-TOF-MS in detecting the milk batch-to-batch variability: Freshly produced milk samples were distinguished based on the week of production at the beginning of shelf life. Additionally, a clear evolution of the volatiles organic compounds (VOCs) profiling during storage was highlighted. Further statistical analysis confirmed VOCs temporal evolution, mostly because of changes in methyl ketones concentration. Differences caused by the commercial lactases did not emerged, except for benzaldehyde. Altogether, data demonstrated PTR-TOF-MS analysis as a valuable and rapid method for the detection of changes in the VOCs profiling of UHT LFM.