Milk and Its Sugar-Lactose: A Picture of Evaluation Methodologies

Effect of lactose on the in vitro development of sheep secondary follicles

Considering that follicular development is an energy-dependent process, supplementation of the culture medium with energy substrates, such as lactose, would improve follicle viability and growth. Thus, the aim of this study was to evaluate the effect of lactose on morphology, development, glutathione (GSH) concentration, mitochondrial activity, DNA fragmentation, and meiotic resumption of oocytes from sheep secondary follicles cultured in vitro. Secondary follicles were isolated from the cortex of ovine ovaries and cultured individually for 18 days in α-MEM supplemented with bovine serum albumin (BSA), insulin, glutamine, hypoxanthine, transferrin, selenium and ascorbic acid (control medium: α-MEM+) or in α-MEM+ plus different concentrations of lactose (0.025, 0.05 and 0.1 M). After culture, some of the oocytes were subjected to TUNEL assay and in vitro maturation (IVM). Follicular morphology, glutathione (GSH) concentration and mitochondrial activity were evaluated at the end of the culture. At the day 18, the percentage of morphologically normal follicles was greater (P<0.05) in the treatment of 0.025 M lactose (92.5 %) compared to the control group (75.55 %). In addition, GSH concentrations increased (P<0.05) in treatment containing 0.025 M lactose compared to the other treatments. Furthermore, oocytes cultured in 0.025 M lactose had greater (P<0.05) mitochondrial activity levels than in α-MEM+ and 0.1 M lactose. The group α-MEM+ presented a increase of TUNEL-positive oocytes (35.09 %) compared to 0.025 lactose (9.09 %). The percentage of meiotic resumption was greater (P<0.05) in oocytes from secondary follicles cultured in 0.025 M lactose (54.5 %) than in α-MEM+ (45.5 %). In conclusion, 0.025 M lactose improved survival, GSH and active mitochondria levels and meiotic resumption of oocytes from in vitro cultured secondary follicles. Supplementation of the culture medium of preantral follicles with lactose can gradually provide energy to follicular cells, potentially enhancing the production of viable oocytes for biotechniques such as IVM and in vitro fertilization.

Donor human milk: the influence of processing technologies on its nutritional and microbial composition

Human milk is regarded as the gold standard nutrition for newborn infants, providing all nutrients required for adequate growth and development from birth to 6 months. In addition, human milk is host to an array of bioactive factors that confer immune protection to the newborn infant. For this reason, the supply of human milk is crucial for premature, seriously ill, or low birth weight infants (<1,500 g). When a mother's own milk is unavailable, donor human milk is the recommended alternative by the World Health Organization. Prior to consumption, donor human milk undergoes pasteurization to ensure the eradication of bacterial agents and prevent the transfer of potentially pathogenic organisms. Currently, Holder Pasteurization, a heat-based treatment, is the widely adopted pasteurization technique used by milk banks. Holder pasteurization has demonstrated degradative effects on some of milk's biologically active factors, thus depleting critical bioactive agents with known functional, protective, and beneficial properties, ultimately reducing the immunoprotective value of donor human milk. As a result, alternative strategies for the processing of donor human milk have garnered much interest. These include thermal and non-thermal techniques. In the current review, we describe the effects of Holder pasteurization and alternative milk processing technologies on the nutritional and bioactive properties of milk. In addition, the capacity of each technique to ensure microbial inactivation of milk is summarized. These include the most extensively studied, high-temperature short-time and high-pressure processing, the emerging yet promising techniques, microwave heating and UV-C irradiation, and the lesser studied technologies, thermoultrasonication, retort processing, pulsed electric field, and gamma irradiation. Herein, we collate the findings of studies, to date, to allow for greater insight into the existing gaps in scientific knowledge. It is apparent that the lack of a cohesive standardized approach to human milk processing has resulted in contrasting findings, preventing a direct comparative analysis of the research. We conclude that donor human milk is a unique and valuable resource to the health sector, and although substantial research has been completed, persistent data disparities must be overcome to ensure optimal nutrition for the vulnerable newborn preterm infant group, in particular.

Process-Induced Molecular-Level Protein-Carbohydrate-Polyphenol Interactions in Milk-Tea Blends: A Review

The rapid increase in the production of powdered milk-tea blends is driven by a growing awareness of the presence of highly nutritious bioactive compounds and consumer demand for convenient beverages. However, the lack of literature on the impact of heat-induced component interactions during processing hinders the production of high-quality milk-tea powders. The production process of milk-tea powder blends includes the key steps of pasteurization, evaporation, and spray drying. Controlling heat-induced interactions, such as protein-protein, protein-carbohydrate, protein-polyphenol, carbohydrate-polyphenol, and carbohydrate-polyphenol, during pasteurization, concentration, and evaporation is essential for producing a high-quality milk-tea powder with favorable physical, structural, rheological, sensory, and nutritional qualities. Adjusting production parameters, such as the type and the composition of ingredients, processing methods, and processing conditions, is a great way to modify these interactions between components in the formulation, and thereby, provide improved properties and storage stability for the final product. Therefore, this review comprehensively discusses how molecular-level interactions among proteins, carbohydrates, and polyphenols are affected by various unit operations during the production of milk-tea powders.

Effects of the COVID-19 Pandemic on Dairy Consumption Trends: An Empirical Investigation of Accounting Data in China

The COVID-19 pandemic may have had a negative impact on dairy consumption trends. Many dairy products are perishable and have relatively high income elasticity, causing their susceptibility to market fluctuations in general, including those specifically caused by the pandemic. However, the pandemic has also brought some other prospective possibilities. For example, during the pandemic, people paid more attention to nutrition and health issues and increased the number of meals prepared and eaten at home. In consideration of the particular circumstances during the pandemic, the Chinese government issued several policies to promote the population's dairy consumption, and the Chinese dairy cattle sector actively implemented the policy of "guarantee price, quality, and supply". These factors may have caused the Chinese population to increase their consumption of dairy products during the pandemic. Before the pandemic, the consumption of dairy products in the Chinese population showed an overall upward trend. The question addressed in this study is how has COVID-19 affected dairy consumption trends during the pandemic? This study uses accounting data from the Chinese dairy cattle sector to empirically analyze the impact of the COVID-19 pandemic on dairy consumption trends through economic theories and translog revenue function. Our study found that COVID-19 increased consumers' consumption of dairy products in China, but those people experiencing poverty may still have experienced inadequate dairy intake. This study has contributed to the body of work in this area in the literature and provides response strategies for the dairy cattle sector and the authorities.

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.

Instant quantification of sugars in milk tablets using near-infrared spectroscopy and chemometric tools

Milk tablets are a popular dairy product in many Asian countries. This research aimed to develop an instant and rapid method for determining sucrose and lactose contents in milk tablets using near-infrared (NIR) spectroscopy. For the quantitative analysis, a training set composed of laboratory-scale milk samples was generated based on a central composite design (CCD) and used to establish partial least squares (PLS) regression for the predictions of sucrose and lactose contents resulting in R² values of 0.9749 and 0.9987 with the corresponding root mean square error of calibration (RMSEC) values of 1.69 and 0.35. However, the physical difference between the laboratory-scale powder and the final product milk tablet samples resulted in spectral deviations that dramatically affected the predictive performance of the PLS models. Therefore, calibration transfer methods called direct standardization (DS) and piecewise direct standardization (PDS) were used to adjust the NIR spectra from the real milk tablet samples before the quantitative prediction. Using high-performance liquid chromatography (HPLC) as a reference method, the developed NIR-chemometric model could be used to instantly predict the sugar contents in real milk tablets by producing root mean square error of prediction (RMSEP) values for sucrose and lactose of 5.04 and 4.22 with Q² values of 0.7973 and 0.9411, respectively, after the PDS transformation.

Potential of New Bacterial Strains for a Multiproduct Bioprocess Application: A Case Study Using Isolates of Lactic Acid Bacteria from Pineapple Silage of Costa Rican Agro-Industrial Residues

Lactic acid bacteria (LAB) with potential for the development of multi-product processes are necessary for the valorization of side streams obtained during the biotechnological production of lactic acid (LA). In this study, 14 LAB strains isolated from pineapple agro-industrial residues in Costa Rica were cultivated in microplates, and the six strains with the highest growth were selected for fermentation in microbioreactors to evaluate the production of LA and acetic acid, and the consumption of glucose. Lacticaseibacillus paracasei 6710 and L. paracasei 6714 presented the highest OD600 values (1.600 and 1.602, respectively); however, the highest LA (in g/L) production was observed in L. paracasei 6714 (14.50 ± 0.20) and 6712 (14.67 ± 0.42). L. paracasei 6714 was selected for bioreactor fermentation and reached a maximum OD600 of 6.3062 ± 0.141, with a LA yield of 84.9% and a productivity of 1.06 g L−1 h−1 after 21 h of fermentation. Finally, lipoteichoic acid (LTA) detection from biomass was performed and the antimicrobial activity of the compounds present in the supernatant was studied. LTA was detected from L. paracasei 6714 biomass, and its supernatant caused significant inhibition of foodborne surrogate microorganisms. LAB isolated from pineapple silage have biotechnological potential for multiproduct processes.

The Association of Lactose Intolerance With Colon and Gastric Cancers: Friend or Foe?

Background: Lactose intolerance (LI) appears usually in later ages when the lactase enzyme becomes deficient or absent in the small intestine. Conflicting results have been reported in the literature about the association of lactose intolerance with various gastrointestinal malignancies. Hence, our aim was to study the association between LI, colon cancer (CCa), and gastric cancer (GC) using a large database. Methods: A cross-sectional study was performed using the National Inpatient Sample (NIS) database between 2004 and 2014. We identified adult patients (18-90 years) who were diagnosed with LI (study group) using appropriate International Classification of Diseases, Ninth Revision (ICD-9) codes. The control group comprised patients who did not have a diagnosis of LI. We identified the diagnosis of CCa and GC in both study and control groups using the ICD-9 codes. Univariable and multivariable logistic regression analyses were performed to assess the association between LI, CCa, and GC. Results: The total population comprised 71,360,501 patients, of which 57,909 (0.08%) were diagnosed with LI. LI patients were older (62 vs 51 years) with more females (61.5% vs 60.1%) and less African American patients (11.8% vs 14.3%) (p <0.0001 for all). In addition, LI patients had more smoking (12.4% vs 12%) and obesity (15% vs 8.9%). On the other hand, patients in the LI group had less alcohol use (3.8% vs 4.2%) (p <0.0001). After adjusting for the age, gender, race, smoking, alcohol, obesity, and inflammatory bowel disease, the LI group had a slightly lower rate of CCa (OR 0 .974, 95%CI 0.906-1.048, p = 0.486) and a lower rate of GC (OR: 0.993, 95%CI 0.924-1.068, p =0.853); however, the results were not statistically significant. Conclusion: Patients with lactose intolerance may have a lower risk of colon and gastric cancer. However, these findings were not statistically significant. Further studies are needed to understand this association.

Breast Milk: A Meal Worth Having

A mother is gifted with breast milk, the natural source of nutrition for her infant. In addition to the wealth of macro and micro-nutrients, human milk also contains many microorganisms, few of which originate from the mother, while others are acquired from the mouth of the infant and the surroundings. Among these microbes, the most commonly residing bacteria are Staphylococci, Streptococci, Lactobacilli and Bifidobacteria. These microorganisms initiate and help the development of the milk microbiota as well as the microbiota of the gastrointestinal tract in infants, and contribute to developing immune regulatory factors such as cytokines, growth factors, lactoferrin among others. These factors play an important role in reducing the risk of developing chronic diseases like type 2 diabetes, asthma and others later in life. In this review, we will summarize the known benefits of breastfeeding and highlight the role of the breast milk microbiota and its cross-talk with the immune system in breastfed babies during the early years of life.

Single nucleotide polymorphisms and metabolic biochemical profile of productive markers characterize three European breeds of dairy cattle

The objective of this study was to investigate polymorphisms of DGAT1, FABP, OLR1 and ATP1A1 genes using PCR-DNA sequencing, and to associate these genetic structures to changes in metabolic biochemical markers and milk composition indicators in a total of 90 dairy cows of the Holstein, Simmental, and Brown Swiss breeds (30 cows each). PCR was carried out for amplification of 411-bp of DGAT1, 525-bp of FABP, 582-bp of OLR1, and 300-bp of ATP1A1 genes. Three breeds’ nucleotide sequence variations in the form of single nucleotide polymorphisms (SNPs) were detailed by DNA sequencing analysis. Chisquare analysis showed that the distribution of all discovered SNPs varied significantly (P < 0.001). Biochemical indices in cow’s serum revealed no significant difference in serum total protein, albumin, and total cholesterol among the three breeds. However, triglyceride showed a significant increase in Simmental compared to either Holsteins or Brown Swiss, while the highest mean value of triiodothyronine (T3) and tetraiodothyronine (T4) was detected in Holstein dairy cows The milk composition indicators analysis revealed that milk protein, sugar, and density were significantly higher in Holsteins than both Simmental and Brown Swiss. Meanwhile, milk fat and total solids revealed a significantly higher increase in Simmental than both brown Swiss and Holstein. As a result, the metabolic biochemical markers profile along with the identified SNPs could be used as a candidate and a reference guide for effective characterization of the Holstein, Simmental, and Brown Swiss breeds, leading to the creation of a marker-assisted selection system for production traits in dairy cattle breeds.

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.

Non-enzymatic lactose molecularly imprinted sensor based on disposable graphite paper electrode

Lactose (LAC) is a disaccharide - major sugar, present in milk and dairy products. LAC content is an important indicator of milk quality and abnormalities in food industries, as well as in human and animal health. The present study reports the development of an innovative imprinted voltammetric sensor for sensitive detection of LAC. The sensor was constructed using electropolymerized pyrrole (Py) molecularly imprinted polymer (MIP) on graphite paper electrode (PE). The MIP film was constructed through the electrosynthesis of polypyrrole (PPy) in the presence of LAC (template molecule) on PE (PPy/PE). To optimize the detection conditions, several factors affecting the PPy/PE sensor performance were assessed by multivariate methods (Plackett-Burman design and central composite design). Under optimized conditions, the proposed analytical method was applied for LAC detection in whole and LAC-free milks, where it demonstrated high sensitivity and selectivity, with two dynamic linear ranges of concentration (1.0-10 nmol L^-1 and 25-125 nmol L^-1) and a detection limit of 0.88 nmol L^-1. The MIP sensor showed selective molecular recognition for LAC in the presence of structurally related molecules. The proposed PPy/PE sensor exhibited good stability, as well as excellent reproducibility and repeatability. Based on the results obtained, the PPy/PE is found to be highly promising for sensitive detection of LAC.

Growth conditions and survival kinetics during storage of Lactobacillus rhamnosus GG for the design of a sustainable probiotic whey-based beverage containing Costa Rican guava fruit pulp

The finding of economical and practical applications for milk whey is still a challenge for dairy industries. This paper presents information about the development of a probiotic-prebiotic beverage based on Lactobacillus rhamnosus GG (LGG) and Costa Rican guava (CRG) fruit pulp with industrial potential. First, a supplemented whey media was developed for LGG growth, and the whey-supplemented media was used for fermentation in bioreactors. LGG reached a maximum growth rate of 0.32 hr^-1 after 48 hr of fermentation. The whey-grown probiotics were then mixed with CRG pulp to produce the probiotic-prebiotic beverage. The survival kinetics of LGG in the formulated drink was not affected by the addition of CRG pulp (P > 0.05), and the shelf-life of the inoculated beverage surpassed 40 days with a minimum population of 10⁶ colony forming units (CFU)/mL. Properties as pH, fructose, glucose, sucrose, and proanthocyanidins (PACs) content exhibited a significant difference after storage time (P < 0.05). Finally, three different formulas of the beverage with different whey content were compared through sensory evaluation. The prototype with 50% whey content was one of the most valuable beverage formulas according to the organoleptic parameters, which remarks about the possibility of developing a probiotic whey-based beverage containing CRG pulp. Furthermore, this is the first report about CRG beverages as a probiotic vector. PRACTICAL APPLICATION: This research focuses on the evaluation of the properties of a probiotic beverage, with a promissory industrial application using whey, as a dairy industry byproduct, combined with the pulp of the highly nutritious and subutilized Costa Rican guava (CRG) fruit.