Low Lactose Research Articles

Low Lactose Yogurt with Blueberry Jam: Development and Sensory Acceptance

Introduction: The lactose-intolerant public represents an important portion of the population; however, the diversification of products that serve this population is still very limited. Objective: In this bias, this study aimed to develop a low-lactose yogurt added with blueberry jelly, combining sensory and functional characteristics of the fruit. Methods: Different concentrations of β-galactosidase were evaluated in the fermentations, in addition to four formulations of blueberry jelly that were sensorially tested for preference, a formulation was selected and its global acceptance and purchase intent were verified. Results: The use of 1.5 g L- 1 of β-galactosidase allowed for a more significant reduction of lactose during the fermentation process. Of the four jelly formulations tested, the whole fruit was sensory preferred, and the low-lactose two-layer yogurt showed 86% acceptance and 74% purchase intention. Conclusion: It was possible to develop a product with low lactose content and sensorially pleasant to the consumer.

“Milk on Ice”: A detailed analysis of Ernest Shackleton's century-old whole milk powder in comparison with modern counterparts

Whole milk powder (WMP) manufactured in New Zealand in 1907 was sent to the Antarctic continent with the Shackleton-led British Antarctic Expedition from 1907 to 1909. This powder was stored at ambient conditions at Shackleton's Hut at Cape Royds, Antarctica, for over 100 yr before a sample was collected on behalf of Fonterra by the Antarctic Heritage Trust. Having spent most of its existence both dried and in frozen storage, any deleterious reactions within the WMP would have been markedly retarded. The composition and some properties of the roller-dried Shackleton's WMP are reported along with those of 2 modern spray-dried New Zealand WMP. The Shackleton powder was less white and more yellow than the modern WMP and was composed of flakes rather than agglomerated particles, consistent with that expected of a roller-dried powder. Headspace analysis showed lipolytic and oxidative volatile compounds were present in the Shackleton WMP, indicting some deterioration of the milk either before powder manufacture or on storage of the finished product. On a moisture-free basis, the Shackleton WMP had higher protein, higher fat (with a markedly higher free fat level), higher ash, and a lower lactose level than the modern WMP. The lysine level was lower in the Shackleton WMP compared with the spray-dried powders, whereas the fatty acid composition was relatively similar. The sodium level was markedly higher in the Shackleton WMP compared with the spray-dried powder, which is probably due to the addition of an alkaline sodium salt to adjust the pH of the milk before roller drying. Lead, iron, and tin levels were markedly higher in the Shackleton WMP compared with the spray-dried powders, possibly due to the equipment used in powder manufacture and the tin-plated cases used for storage. The proteins in the Shackleton WMP were more lactosylated than in the spray-dried powders. The Shackleton WMP had a higher ratio of κ-casein A to B variants and a higher ratio of β-lactoglobulin B to A variants than the spray-dried powders, whereas the αS1-casein, β-casein, αS2-casein, and α-lactalbumin protein variants were similar in all powders. The total phospholipid content was markedly lower in the Shackleton WMP than the spray-dried powders, primarily due to a lower phosphatidylethanolamine concentration. The molecular species distributions within the phospholipid classes were generally similar in the 3 powders. Claims are sometimes encountered that the milk of today is different from that consumed by previous generations. However, this comparative study has shown that the Shackleton WMP was generally similar to modern WMP. Although differences in some components and properties were observed, these were attributable to the manufacturing equipment and processes used in the pioneering years of WMP manufacture.

Water-soluble oat extract enriched with mango peel flour: preparation, characterization and application in Greek yogurt.

This study aimed to produce water-soluble oat extract enriched with mango peel flour (MPF) as a source of active compounds and to use this ingredient as a partial substitute for whole milk in Greek yogurt (GY) for its nutritional enrichment. Enriched water-soluble oat extracts (EWSOE) were produced with different concentrations of MPF (0%, 1%, 1.5% and 2%) and characterized in relation to pH, titratable acidity, soluble proteins and total phenolics. Three GY formulations were prepared by partially replacing whole milk with EWSOE and the best formulation (in relation to sensory analyzes and phenolics compounds) was selected for storage study, chemical characterization, and sensory acceptance testing. MPF addition increased soluble proteins and total phenolics in EWSOE. GY formulations prepared with EWSOE had similar sensory scores. During storage, GY prepared with EWSOE containing 2% MPF exhibited changes in pH and titratable acidity and a reduction in total phenolics. Color parameters, cholesterol, and fatty acid composition did not change over 21 days of storage. The major fatty acids in GY were oleic and palmitic acids. The selected product had low lactose content (1.2%), achieved satisfactory sensory acceptance in relation to the evaluated attributes, and had lipid (~6.19%) and protein (~3.96%) contents within regulatory requirements. Additionally, EWSOE is a valuable ingredient in GY preparation, offering beneficial nutritional and functional properties.

Keçilerde Laktasyona Fizyolojik Bir Bakış: Derleme

The domesticated species of goats, scientifically known as Capra hircus, have played a significant role in several aspects of human existence over the course of history. These animals have made notable contributions to both individual animal breeding practices and the overall national economy. Their unique meat and milk production, along with their ease of cultivation, distinguish them as noteworthy entities. Goat milk is widely favored by customers due to its hypoallergenic features, low lactose levels, and rich composition. As a result, goat breeding has been prevalent in our country and globally for milk production in animal husbandry. In accordance with the purpose of achieving a high-quality final product, which constitutes a primary goal of animal husbandry, it is important to possess knowledge on certain attributes relating to the animal under cultivation. The aforementioned characteristics pertain to the anatomical composition of the udder and the physiological processes involved in breastfeeding in goats. Lactation physiology encompasses three key processes: mammogenesis, lactogenesis, and galactopoiesis. Mammogenesis refers to the formation of the udder, while lactogenesis involves the secretion of milk. Galactopoiesis, on the other hand, pertains to the maintenance of continuous milk supply. This review will examine the reproductive cycle, physical structure, and developmental aspects of the udder, as well as the many stages of lactation physiology in goats.

Characterization and estimation of the bioaccessibility of essential elements in organic milk by INFOGEST protocol

The study estimated the bioaccessibility of calcium, phosphorus and magnesium in organic milk (ORG), compared to conventional (CNV) by the INFOGEST in vitro protocol. Total proteins, lipids and lactose were evaluated, the determination of essential minerals was performed by FAAS and phosphorus by colorimetric method. All ORG samples showed protein content equivalent to CNV and lower lactose and lipid content. Within different brands and batches, two batches of ORG presented higher levels of Na and lower levels of K and P, while all batches showed higher values for Ca and no differences for Mg. The bioaccessibility of magnesium was greater than 60%. ORG showed the highest values of bioaccessible calcium (12–65%) against CNV (11–27%). Phosphorus showed bioaccessibility higher than 74% in CNV. The variability of the results was related to different factors inherent to the matrices, such as casein and fatty-acids content and electrolytes standardized in the protocol.

Ulasan Ilmiah: Karakteristik Mutu Nutrisi, Organoleptik dan Mikrobiologis Kefir Susu Kambing

Kefir is a beverage product obtained through the fermentation process of pasteurized milk using a starter from kefir grain. Kefir can be made using goat's milk. Processing of goat milk into kefir is a method used to increase the fat, protein and carbohydrate content of goat milk. There are many factors that affect the quality of kefir. This study aims to determine the potential of of goat's milk kefir based on nutritional, organoleptic and microbiological parameters. The method used is a literature study that comes from various data sources. The selection of cited journals has gone through a screening process based on inclusion, special and exclusion criteria. The results showed, making goat milk kefir requires 12-36 hour of fermentation proces and using a concentration of kefir grains ranging from 2.5 – 5%. This proces, produces a kefir product with good organoleptic characteristics with a white color, distinctive aroma of kefir, sour taste, and soft texture. Goat milk kefir generally has a protein content of 2.96 – 3.66%, fat 2.02 – 5.35%, carbohydrates 2.45 – 5.6%, ash 0.42 – 0.80, ethanol 0.72% with an acidic pH. Goat's milk kefir has a lower lactose concentration of 0.2-0.5% than cow's milk. It also contains various types of microorganisms, including LAB and yeast, which are present in kefir grains which vary widely, with an amount of around 6.4 x 104 to 8.5 x 108 and 1.5 x 105 to 3.7 x 108 cfu/ml. The number of microbes in the kefir has met the standard as a functional food.

LACTOSE-FREE ICE CREAM TECHNOLOGY BASED ON SECONDARY DAIRY RAW MATERIALS

Expanding the assortment of lactose-free dairy products, namely, ice cream for people who cannot tolerate lactose is a promising direction of research. The purpose of the work is to develop the technology of milk lactose-free synbiotic yogurt ice cream based on buttermilk protein-lipid concentrate, obtained by ultrafiltration/diafiltration, with the addition of natural flavoring and food additives, and the study of its quality indicators. A protein-lipid concentrate of buttermilk with a low lactose content was obtained by ultrafiltration/diafiltration, and its quality indicators were determined. The concentrate has a high protein content (16.01%) and a low lactose content (1.28%). Protein-lipid concentrate fermented with synbiotic sourdough is the main component included in the formulation of lactose-free synbiotic yogurt ice cream. The main physico-chemical parameters of the obtained fermented protein-lipid concentrate were determined, which ensures a rational content of the main components of the chemical composition in the finished lactose-free ice cream (it does not contain lactose, the protein content is 8.46%) and a high content of useful microflora (bifido- and lactobacilli). A mixture for lactose-free synbiotic yogurt ice cream was obtained according to a scientifically based recipe. A sample of lactose-free ice cream was made from the mixture using traditional technology, and organoleptic, physico-chemical and microbiological quality indicators were investigated. A comparison of the quality indicators of the studied sample with the control, which was taken as classic yogurt ice cream, was carried out. The mass fraction of lactose in samples of lactose-free ice cream is 0,011%. The developed lactose-free synbiotic yogurt ice cream has high probiotic activity (contains lacto- (3.0•108 CFU/g) and bifidobacteria (3.5•109 CFU/g)).

Statistical methods and its applications in Whey protein binding (Bos Taurus)

Milk is made up of two proteins, such as casein (80%) and whey (20%). These proteins, which include membrane globular proteins, glycoproteins, and lipoproteins, are mostly found in the outer layer of milk fat globule membranes. WP can be separated from the casein in milk or formed as a byproduct of cheese making and contains all nine essential amino acids with a low lactose content. Whey protein has many health benefits, including improving strength and body composition, promoting weight loss, boosting metabolism, stifling hunger, maintaining good health, avoiding nourishing the bones, reducing inflammation, promoting quick wound healing, lowering blood pressure, repairing and preserving muscle tissues etc. Many dairy and food-based industries eagerly explore the accurate retention time for the formation of health related new byproducts. As of date, there are very few studies available in the world literature citation database and too many micro and macro studies on WP are currently being undertaken globally, they provide insight into the binding of particular amino acids (Seq. peptides) and their accurate lag time of binding to the formation of "helixes and sheaths. In this paradigm, statistical tool are very important to determine average time and WP algorithms for analysis of seq amino acids and the metabolic pathway's action. Overall, the present research attempts to extrapolate the Seq peptide's binding capacity and its retention time for amino acids in order to fill the aforementioned research gap. For the model demonstration we used the commonly cited whey protein peptide (Seq) NCBS, which was considered to prove the hypothesis. The Markova two state random and Monte Carlo simulation (superimposed artificial neural network) models were formulated to extract transient probabilities and retention times of Seq peptides. As per the results, the binding capacity was found to be excellent with a good retention time (5 to 11.50 minutes) in cross-linked and unlinked cases (10 to 13.50 minutes). Bioinformatics, the dairy industry, and life scientists will find these more recent discoveries to be very helpful for measuring likelihoods and transient probabilities of binding.

Donkey milk: chemical make-up, biochemical features, nutritional worth, and possible human health benefits - Current state of scientific knowledge

Milk and milk derivatives are widely consumed because of their high nutritional density. Donkey milk and milk products have been consumed since ancient times. The use of donkey milk in the human diet is gaining popularity. The abundance of antibacterial components and protective elements in donkey milk sets it apart from the milk of other animals. Like human milk, donkey milk has low fat, high lactose, and low casein/whey protein ratio. Donkey milk whey protein's anti-proliferative properties imply lung cancer treatment. Alpha-lactalbumin, a type of protein, has been found to have antiviral, anticancer, and anti-stress properties. Donkey milk, like human milk, includes a low amount of casein and a smaller quantity of beta-lactoglobulin than cow milk. Donkey milk is an alternative for newborns with cow milk protein allergy and lactose intolerance since it has a higher amount of lactose, improves palatability, and prevents allergies. Osteogenesis, arteriosclerosis therapy, cardiac rehabilitation, accelerated aging, and hypocholesterolemic diets are some areas where donkey milk is beneficial. Since it contains probiotic lactobacilli strains, fermented beverages can be made with donkey milk. Donkey milk moisturizes skin due to its high vitamin, mineral, and polyunsaturated fatty acid content. The chemical makeup and potential therapeutic benefits of donkey milk warrant additional research. This has led to a rise in interest in producing dairy goods derived from donkey milk. Donkey milk has been used to make cheese, ice cream, milk powder, and even some experimental useful fermented drinks. The present article summarises what we know about donkey milk's chemical makeup, biological functions, nutritional worth, and possible human health benefits.

EFEK WAKTU AGING DAN PENGERINGAN VAKUM PADA ANALISIS PROKSIMAT DAN TINGKAT ASAM AMINO DARI KEFIR SUSU KAMBING

Goat milk kefir has high nutritional value, especially in protein and calcium content and has a low lactose content. Vacuum drying is an alternative to remove the water content in kefir so that it can extend the shelf life because it inhibits bacterial growth. This study determines the effect of aging time and drying time using vacuum drying method on the characteristics and amino acid composition of goat milk kefir (kefir and powder kefir). Fermented goat milk (24 hours) use kefir grains without aging and with aging times of 1, 2, 3, 4 (week). The total titrated acid and fat content were significantly different in kefir, but it is not significantly different in powder kefir. The yield, moisture, ash, protein, fiber, and fat in both kefir and powder kefir did not show significant differences. The best treatment based on the exponential comparison method for both powder kefir and kefir was 3 weeks of aging time. Therefore, the amino acid components in powder kefir and kefir underwent changes. The highest total amino acids in kefir was kefir without aging. The highest amino acid of powder kefir was obtained after 2 weeks of aging time.

Optimization of Tacrolimus Loaded Reconstituted Nanoparticles by QbD Method

The aim of the present study is to implement QbD approach for development and optimization of Tacrolimus Loaded Reconstituted Nanoparticles. Tacrolimus-loaded nanoparticles were prepared by using Kollisolve PEG 300, Kolliphor ELP, Citrate buffer solution and Tween 80. The aqueous medium was added drop by drop into the organic phase at continuous stirring on a magnetic stirrer for half an hour. The solution then homogenized at high pressure that reduced particle size. Drying was done by using Low Endotoxin Lactose Monohydrate as a carrier. The final reconstituted powder stored in a closed container and assessed for zeta potential, drug loading, FT-IR Studies, Particle Size Analysis, SEM, X-Ray Diffraction, DSC etc. Optimization was performed by using Design Expert 8 software, 3 Level Factorial design was selected from Response Surface Design. The drug was found to be 98.65% w/w by assay. The particle size was found to be in the range of 263nm - 500nm. Tacrolimus powder shows O-H stretching vibration at 3374.91cm−1, C = O stretching vibrations at 1733.38 cm−1, and C = C stretching vibration at 1631.55 cm−1, C–O (ester) stretching vibration at 1248.11 cm−1. Tacrolimus nanoparticles were optimized by QbD method, Methanol: Phosphate Buffer (80:20) solvent phase was used having pH 6. The maximum wavelength of Tacrolimus was found to be 293nm. The desirability value of that optimized method was found to be 1. Tacrolimus Loaded Reconstituted Nanoparticles leads to enhanced solubility and we can conclude that an increase in pH was responsible for increment in absorbance and thus showed the direct relationship between them.

LACTOSE INTOLERANCE

Introduction: Lactose intolerance in children in early childhood has been increasing the level of intolerance, evidencing in the child’s growth and development phases, being vital during the consumption of milk. Presenting symptoms and food discomfort due to the consumption of milk. Lactose intolerance can be classified as primary, when there is an intrinsic defect of the enzyme; or secondary, when there is a damage to the intestinal mucosa with consequent lack of it. Objective: This research aims to describe the conduct of the nutritionist towards children with lactose intolerance in early childhood based on literary reports. Method: Study of integrative literature review, descriptive and exploratory, with the purpose of presenting issues related to nutritional conduct in the care of children in early childhood. For this, information will be selected in other articles, found on search sites: SCIELO, PubMed and Google Scholar. The sample population will be composed of articles recently published between the years 2016 to 2020, and in accordance with the pre-established inclusion and exclusion criteria. The selection will take place in the month of May 2021. Results. It was found among the investigated productions that most of them are about nutritional characteristics, including the concern with calcium deficiency and alternatives to substitute products that develop symptoms by those that have low lactose content. Among the metabolic aspects were not the main focus of the articles found, however, only one article addressed this topic. Conclusions: Therefore, nutritionists play a fundamental role in the improvement and quality of life of children in early childhood, which will collaborate for their growth and healthy development, under the conditions presented, to provide information to parents about diseases and nutritionally adequate substitutes.

P499 Exclusive enteral nutrition induces transmural healing in adults with active Crohn’s disease

Abstract Background Exclusive enteral nutrition (EEN) is a nutrition-based therapy for active Crohn’s Disease (CD). Transmural healing is a novel therapeutic paradigm in CD, holding benefit beyond endoscopic mucosal healing. There are limited data exploring EEN and transmural healing in CD. We aimed to examine the effect of EEN on inducing transmural response and healing as assessed by intestinal ultrasonography (IUS). Methods This was a prospective, multi-centre, open-label cohort study. Adults ≥18 years with active CD were enrolled between March to September 2022. Eligible, consenting participants were nutritionally assessed by a specialised IBD dietitian and prescribed 6 weeks of EEN therapy. A 1.5kcal/ml polymeric, low lactose, fibre-free formula was used and EEN prescriptions were personalised to 25-30kcal/kg IBW and 1.2-1.5g protein/kg IBW/day. Patients were allowed concurrent tapering corticosteroid therapy and biological therapy. Participants completed clinical, biochemical and nutritional assessments at weeks 0, 3 and 6 and IUS at weeks 0 and 6. This included Harvey Bradshaw Index (HBI), C-Reactive protein, faecal calprotectin (FCP), body mass index (BMI). IUS assessment was conducted at baseline and at week 6 and images were centrally read by a blinded, IUS-trained gastroenterologist. Transmural response was defined by ≥25% bowel wall thickness (BWT) reduction from baseline. Transmural healing was defined as BWT≤3mm, Doppler signal score≤1, normal bowel wall stratification, and absence of inflammatory fat. Results Fourteen patients, 9 were female (64.3%) and mean age of 44.4 years, were consecutively enrolled and completed 6-weeks of EEN therapy. Ten patients (71.4%) had ileal disease (L1), 4/10 had ileocolonic (L3) and predominant phenotype was inflammatory (B1, 7/14) and stricturing (B2, 6/14) disease. Mean disease activity was HBI 5.1±4.0.Two patients had perianal disease (14.3%). Nine patients (64.3%) reported 100% adherence and 4 patients (28.6%) reported 75-99% adherence to the exclusive diet by predefined adherence categories. At week 6, 11/14 (78.6%) of patients achieved clinical remission with 12/14 (85.7%) showing clinical response. Reductions in CRP and FCP were not statistically significant. Numerical reduction in BWT was observed 5.6±1.4mm vs 4.8±2.1mm (95% CI -1.94, 0.265, p = 0.124). Transmural response was achieved in 8/14 (57.1%) and transmural healing was reached in 2 (14.3%) patients. Most common side effect was constipation (42.9%). Conclusion EEN was identified to induce early transmural response and healing in patients with active CD. Further studies are required to evaluate the capacity for EEN to induce transmural healing and the role of IUS as an early assessment tool in monitoring therapeutic response in CD.

Determination of the lactose content in low-lactose milk using Fourier-transform infrared spectroscopy (FTIR) and convolutional neural network

Demand for low lactose milk and milk products has been increasing worldwide due to the high number of people with lactose intolerance. These low lactose dairy foods require fast, low-cost and efficient methods for sugar quantification. However, available methods do not meet all these requirements. In this work, we propose the association of FTIR (Fourier Transform Infrared) spectroscopy with artificial intelligence to identify and quantify residual lactose and other sugars in milk. Convolutional neural networks (CNN) were built from the infrared spectra without preprocessing the data using hyperparameter adjustment and saliency map. For the quantitative prediction of the sugars in milk, a regression model was proposed, while for the qualitative assessment, a classification model was used. Raw, pasteurized and ultra-high temperature (UHT) milk was added with lactose, glucose, and galactose in six concentrations (0.1–7.0 mg mL−1) and, in total, 432 samples were submitted to convolutional neural network. Accuracy, precision, sensitivity, specificity, root mean square error, mean square error, mean absolute error, and coefficient of determination (R2) were used as evaluation parameters. The algorithms indicated a predictive capacity (accuracy) above 95% for classification, and R2 of 81%, 86%, and 92% for respectively, lactose, glucose, and galactose quantification. Our results showed that the association of FTIR spectra with artificial intelligence tools, such as CNN, is an efficient, quick, and low-cost methodology for quantifying lactose and other sugars in milk.

Application of Non-Enzymatic Lactate Sensor Modified by Graphitic Carbon Nitride/Iron–Platinum Nanoparticles and Combined With the Low Power Consumption Instrumentation Amplifier and Calibration Readout Circuit

In a previous study, this laboratory produced and tested a lactic acid biosensor using a copper-doped zinc oxide (CZO) sensing film modified with graphite carbon nitride (g-C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) and iron platinum nanoparticles (FePt NPs). The previous sensor exhibited two non-ideal effects during persistent use and when alternating between high and low lactose concentrations. Using a low unity-gain frequency and low power consumption instrumentation amplifier (UGFPCIA) in conjunction with a calibration readout circuit, it was possible to reduce the previously observed drift and hysteresis effects. The UGFPCIA and calibration readout circuit were connected to a voltage-time (V-T) measurement system so the effects could be accurately quantified. The influence of the UGFPCIA on the measurement characteristics of the lactate biosensor were recorded and compared to a similar device using a commercial LT1167. Results showed that the UGFPCIA produced a more stable measurement, where linearity increased from 0.985 to 0.998. When measuring interference effects, the fluctuation in response voltage became smaller, and the time drift effect was successfully reduced by 89.7%. The hysteresis effect reduced the forward period by 0.13 mV, and the reverse period by 4.37 mV.

Association of High Somatic Cell Counts Prior to Dry off to the Incidence of Periparturient Diseases in Holstein Dairy Cows.

Intramammary infections (mastitis) of dairy cows, along with other periparturient diseases, have become problematic within the dairy industry as they lead to loss of milk production. The main objective of this study was to determine whether elevated somatic cell counts (SCC) in cows prior to drying off are related to the incidence of other periparturient diseases. Additionally, we determined whether milk composition and milk yield are affected by a high SCC prior to drying off. Somatic cell counts of milk samples were determined prior to dry off (n = 140) and were used to classify cows in the study as high (&gt;200,000 cells/mL) or low (&lt;200,000 cells/mL) SCC. The composition of milk was analyzed before drying off and at 1 and 2 weeks after calving. The results showed that an elevated SCC before drying off was related to the incidence of ketosis. Cows with a high SCC at drying off also showed an increased likelihood of retained placenta, metritis, and lameness postpartum; however, it was not statistically significant. Milk lactose was lower in cows with high SCC, whereas protein content was lower after parturition. Milk production was lower for cows with pre-drying elevated SCC, particularly for cows with retained placenta, ketosis, and mastitis. In conclusion, cows with pre-drying elevated SCC were more likely to develop disease after parturition and produce less milk and with lower lactose and protein content.

Heat treatment of milk protein concentrates affects enzymatic coagulation properties

Dairy ingredients with highly concentrated protein contents are high added value products with expanding market. The manufacture of such ingredients includes a succession of unit operations of which heat treatment is a key step to guarantee the microbial safety, that induces major changes in protein structures and thus ingredients functionalities. However, due to an incomplete understanding of phenomena taking place at high protein concentrations, shedding light on their mechanisms is a scientific challenge as well as an industrial need. In this study, the influence of heat treatment (74 °C/ 30 s) of highly concentrated milk protein systems (up to 20 % w/w) on protein denaturation/aggregation and enzymatic coagulation properties was studied using an original semi–industrial approach. 10 % w/w protein solutions constituted with whey protein and casein micelles at milk ratio, standardized in osmosed water or ultrafiltration permeate were used. These protein solutions were processed in different ways prior the manufacture of powders: heat treatment of the 10 % w/w protein solution before vacuum evaporation, heat treatment of the 20 % w/w protein solution after vacuum concentration, two consecutive heat treatments before and after vacuum evaporation. A fourth powder was prepared from unheated 10 % w/w protein solution. An increase in protein concentration led to a higher heat-induced protein denaturation. This phenomenon was reduced when increasing the lactose content. The effect of heat treatment on the extent of protein denaturation was not cumulative. At high protein concentration, interactions between κ-casein and whey protein were modified compared to milk, as mainly micelle-bound aggregates were formed at pH about 6.7. This phenomenon was enhanced at low ionic strength and lactose content. Our study showed that the enzymatic coagulation properties of reconstituted protein powders could be correlated with their physico–chemical compositions. An increase in protein denaturation disrupted the gel reorganization and led to the formation of weaker gels but did not interfere on the micelles aggregation phase and the early gelation. On the contrary, an increase in ionic strength and lactose content led to higher gel time.

Enhanced thermal stability of the β-galactosidase BgaB from Bacillus circulans by cyclization mediated via SpyTag/SpyCatcher interaction and its use in galacto-oligosaccharides synthesis

Cyclization of proteins using SpyTag/SpyCatcher is a novel approach to increase their thermal stability. In this paper, we test this approach on two β-galactosidases from Bacillus circulans, BgaB and BgaC, and find that BgaB was stabilized while BgaC was not. Wild-type BgaB precipitated completely upon heating above 70 °C, but after SpyRing cyclization, it remained soluble after heating to 90 °C. Similarly, wild-type BgaB retained only 50 % activity after heating at 60 °C for 10 min, but this increased to 80 % after SpyRing cyclization. In contrast, cyclization decreased the stability of BgaC. After SpyRing cyclization, BgaC only retained 2 % activity after 20-min incubation at 55 °C, whereas the wild-type BgaC retained 25 % activity. One reason for the different effect of cyclization may the shorter distance between the N- and C-termini in BgaB (20.2 Å) as compared to BgaC (43.7 Å). The intrinsic fluorescence and circular dichroism spectra suggested that SpyRing cyclization of BgaB did not significantly change its conformation or secondary structure. SpyRing cyclized BgaB yielded similar amounts and compositions of galacto-oligosaccharides using a high initial lactose concentration (40 %, w/v), but a slightly higher amount at low initial lactose concentration (5 %, w/v) suggesting increased transgalactosylation activity.

Effects of low lactose mare's milk yogurt consumption on gut microbiota function

Background: This study shows that the intake of low-lactose yogurt with the addition of mare's milk can affect the composition, biodiversity, and functional potential of the intestinal microflora.Purpose of the study: To study the effect of low-lactose drinking yogurt from a combination of mare's and cow's milk on the composition and functional repertoire of the fecal microbiota of rats.Methods: The study of the effect of low-lactose drinking yogurt from a combination of mare's and cow's milk on the intestinal microflora was carried out by dietary intervention for 4 weeks. Changes in the fecal microbiota were determined using V1-V3 sequencing of the hypervariable target region of the 16S rRNA gene. Functional prediction was carried out on the basis of the taxonomic structure of the amplicon sequence.Results: The results demonstrated a decrease in overall biodiversity both within the samples and between groups of animals. Discriminatory analysis revealed an increase in the relative content of Ruminococcaceae, Peptostreptococcaceae, indeterminate taxon at phylum level, Prevotellaceae and a decrease in Helicobacteraceae, Eubacteriumcoprostanoligenes group, Muribaculaceae, Lachnospiraceae, Lactobacillaceae. In addition, changes in the microbial structure also affected the predicted functional repertoire of the gut microbiota.Conclusion: These results demonstrate the consumption of low-lactose drinking yogurt from a combination of mare's and cow's milk, for a short time, can affect the composition and functional repertoire of the fecal microbiota. Keywords: Gut microbiome, rats, low-lactose yogurt, microbial diversity, functional repertoire.

Application of Immobilized Lactase in Flexible and Biodegradable Films to Obtain Milk with Low Lactose Concentration

Application of Immobilized Lactase in Flexible and Biodegradable Films to Obtain Milk with Low Lactose Concentration