Kvaliteta otvorenog konzumnog mlijeka tijekom hladnog skladištenja u kućanstvu

Aim of the study was to determine the effect of the duration of storage of opened drinking milk (pasteurized, micro-filtered and UHT) under home refrigeration conditions on indicators of its freshness (acidity and TBC), nutritional value (contents of fat, protein, lactose, dry matter, nondenatured whey proteins and free fatty acids) and organoleptic characteristics. Refrigeration was found to ensure that opened micro-filtered and pasteurized milk was suitable for consumption for 4 days and UHT milk for at least 7 days. Significant changes in the quality characteristics of protein and fat fractions were not observed until the 7th day of storage. The greatest changes in the content of whey proteins were observed in micro-filtered milk, expressed as decrease of individual proteins of about 20 % each. Pasteurized milk was the most susceptible to lipolysis that resulted in the greatest quantity of saturated free fatty acids. Lipolytic changes affected the acidity of product and thereby led to slight changes in its odor and flavor.Cilj istraživanja bio je utvrditi učinak trajanja skladištenja otvorenog konzumnog mlijeka (pasterizirano, mikrofiltrirano i UHT) u uvjetima hlađenja u kućanstvu na pokazatelje njegove svježine (kiselost, ukupan broj bakterija), nutritivnu vrijednost (sadržaj masti, proteina, laktoze, suhe tvari, ne-denaturiranih proteina sirutke i slobodnih masnih kiselina) i organoleptička svojstva. Hlađenje je pokazalo da je otvoreno mikrofiltrirano i pasterizirano mlijeko prikladno za konzumaciju 4 dana, a UHT mlijeko najmanje 7 dana. Značajne promjene u svojstvima kvalitete proteina i frakcija masti nisu bile utvrđene do 7. dana skladištenja. Najveće promjene u sadržaju proteina sirutke utvrđene su u mikrofiltriranom mlijeku, što se očitovalo kroz smanjenje udjela pojedinih frakcija proteina u iznosu od 20 %. Pasterizirano mlijeko bilo je najosjetljivije na lipolizu, što je rezultiralo najvećom količinom slobodnih zasićenih masnih kiselina. Lipolitičke promjene utjecale su na kiselost proizvoda i time dovele do neznatnih promjena u njezinom mirisu i okusu

The Ability of a Novel Strain Scheffersomyces (Syn. Candida) shehatae Isolated from Rotten Wood to Produce Arabitol

Arabitol is a polyalcohol which has about 70% of the sweetness of sucrose and an energy density of 0.2 kcal/g. Similarly to xylitol, it can be used in the food and pharmaceutical industries as a natural sweetener, a texturing agent, a dental caries reducer, and a humectant. Bio­technological production of arabitol from sugars represents an interesting alternative to chemical production. The yeast Scheffersomyces shehatae strain 20BM-3 isolated from rotten wood was screened for its ability to produce arabitol from L-arabinose, glucose, and xylose. This isolate, cultured at 28°C and 150 rpm, secreted 4.03 ± 0.00 to 7.97 ± 0.67 g/l of arabitol from 17–30 g/l of L-arabinose assimilated from a medium containing 20–80 g/l of this pentose with yields of 0.24 ± 0.00 to 0.36 ± 0.02 g/g. An optimization study demonstrated thatpH 4.0, 32°C, and a shaking frequency of 150 rpm were the optimum conditions for arabitol production by the investigated strain. Under these conditions, strain 20BM-3 produced 6.2 ± 0.17 g/l of arabitol from 17.5 g/l of arabinose after 4 days with a yield of 0.35 ± 0.01 g/g. This strain also produced arabitol from glucose, giving much lower yields, but did not produce it from xylose. The new strain can be successfully used for arabitol production from abundantly available sugars found in plant biomass

Authentication of Polish Red Wines Produced from Zweigelt and Rondo Grape Varieties Based on Volatile Compounds Analysis in Combination with Machine Learning Algorithms: Hotrienol as a Marker of the Zweigelt Variety

The aim of this study was to determine volatile compounds in red wines of Zweigelt and Rondo varieties using HS-SPME/GC-MS and to find a marker and/or a classification model for the assessment of varietal authenticity. The wines were produced by using five commercial yeast strains and two types of malolactic fermentation. Sixty-seven volatile compounds were tentatively identified in the test wines; they represented several classes: 9 acids, 24 alcohols, 2 aldehydes, 19 esters, 2 furan compounds, 2 ketones, 1 sulfur compound and 8 terpenes. 3,7-dimethyl-1,5,7-octatrien-3-ol (hotrienol) was found to be a variety marker for Zweigelt wines, since it was detected in all the Zweigelt wines, but was not present in the Rondo wines at all. The relative concentrations of volatiles were used as an input data set, divided into two subsets (training and testing), to the support vector machine (SVM) and k-nearest neighbor (kNN) algorithms. Both machine learning methods yielded models with the highest possible classification accuracy (100%) when the relative concentrations of all the test compounds or alcohols alone were used as input data. An evaluation of the importance value of subsets consisting of six volatile compounds with the highest potential to distinguish between the Zweigelt and Rondo varieties revealed that SVM and kNN yielded the best classification models (F-score of 1, accuracy of 100%) when 3-ethyl-4-methylpentan-1-ol or 3,7-dimethyl-1,5,7-octatrien-3-ol (hotrienol) or subsets containing one or both of them were used. Moreover, the best SVM model (F-score of 1) was built with a subset containing 2-phenylethyl acetate and 3-(methylsulfanyl)propan-1-ol

Lactoferrin—The Health-Promoting Properties and Contemporary Application with Genetic Aspects

The aim of the study is to present a review of literature data on lactoferrin’s characteristics, applications, and multiple health-promoting properties, with special regard to nutrigenomics and nutrigenetics. The article presents a new approach to food ingredients. Nowadays, lactoferrin is used as an ingredient in food but mainly in pharmaceuticals and cosmetics. In the European Union, bovine lactoferrin has been legally approved for use as a food ingredient since 2012. However, as our research shows, it is not widely used in food production. The major producers of lactoferrin and the few available food products containing it are listed in the article. Due to anti-inflammatory, antibacterial, antiviral, immunomodulatory, antioxidant, and anti-tumour activity, the possibility of lactoferrin use in disease prevention (as a supportive treatment in obesity, diabetes, as well as cardiovascular diseases, including iron deficiency and anaemia) is reported. The possibility of targeted use of lactoferrin is also presented. The use of nutrition genomics, based on the identification of single nucleotide polymorphisms in genes, for example, FTO, PLIN1, TRAP2B, BDNF, SOD2, SLC23A1, LPL, and MTHFR, allows for the effective stratification of people and the selection of the most optimal bioactive nutrients, including lactoferrin, whose bioactive potential cannot be considered without taking into account the group to which they will be given

Impact of Grape Variety, Yeast and Malolactic Fermentation on Volatile Compounds and Fourier Transform Infrared Spectra in Red Wines

Volatile compounds are very important to the flavour and quality of the wine. The study aimed to determine the effect of grape variety (Rondo and Zweigelt), yeast, malolactic fermentation (MLF) and yeast×MLF interaction on the content of volatile compounds in red wines. The wines were produced by sequential inoculation with five commercial yeast strains and a commercial lactic acid bacteria (LAB) strain (induced malolactic fermentation) as well as by inoculation with five commercial yeast strains and without LAB inoculation (spontaneous malolactic fermentation). The volatile compounds were determined by headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME-GC/MS). Forty-six volatile compounds belonging to alcohols, esters, acids, aldehydes, ketones, furan compounds, sulfur compounds and volatile phenols were identified in the wines. The grape variety was the factor with a significant impact on the highest number of volatile compounds, 32 out of 46. Furthermore, 7 compounds were affected by yeast, 10 by MLF and only 3 by yeast×MLF interaction. Characteristic bands in Fourier transform infrared (FTIR) spectra were assigned to the vibrations of functional groups of volatile compounds. The whole FTIR spectra were analysed in detail; three characteristic spectral ranges for different classes of volatile compounds such as 3650-2700, 1750-1500, and below 1500 cm-1 were shown. The most remarkable spectral changes were observed for the last two areas

Protein Hydrolysates Derived from Animals and Plants—A Review of Production Methods and Antioxidant Activity

There is currently considerable interest on the use of animal, plant, and fungal sources in the production of bioactive peptides, as evidenced by the substantial body of research on the topic. Such sources provide cheap and environmentally friendly material as it often includes waste and by-products. Enzymatic hydrolysis is considered an efficient method of obtaining peptides capable of antioxidant activity. Those properties have been proven in terms of radical-scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis-(3-ethyl-benzothiazoline-6-sulphonic acid)), hydroxyl and superoxide radical methods. Additionally, the reducing power, ferrous ion-chelating (FIC), ferric reducing antioxidant power (FRAP), and the ability of the protein hydrolysates to inhibit lipid peroxidation have also been explored. The results collected in this review clearly indicate that the substrate properties, as well as the conditions under which the hydrolysis reaction is carried out, affect the final antioxidant potential of the obtained peptides. This is mainly due to the structural properties of the obtained compounds such as size or amino acid sequences

The production of arabitol by a novel plant yeast isolate Candida parapsilosis 27RL-4

Polyalcohol arabitol can be used in the food and pharmaceutical industries as a natural sweetener, a dental caries reducer, and texturing agent. Environmental samples were screened to isolate effective yeast producers of arabitol. The most promising isolate 27RL-4, obtained from raspberry leaves, was identified genetically and biochemically as Candida parapsilosis. It secreted 10.42– 10.72 g l-1 of product from 20 g l-1 of L-arabinose with a yield of 0.51 - 0.53 g g-1 at 28°C and a rotational speed of 150 rpm. Batch cultures showed that optimal pH value for arabitol production was 5.5. High yields and productivities of arabitol were obtained during incubation of the yeast at 200 rpm, or at 32°C, but the concentrations of the polyol did not exceed 10 g l-1. In modified medium, with reduced amounts of nitrogen compounds and pH 5.5-6.5, lower yeast biomass produced a similar concentration of arabitol, suggesting higher efficiency of yeast cells. This strain also produced arabitol from glucose, with much lower yields. The search for new strains able to successfully produce arabitol is important for allowing the utilization of sugars abundant in plant biomass

A co-utilization strategy to consume glycerol and monosaccharides by Rhizopus strains for fumaric acid production

Abstract The ability of Rhizopus oryzae to produce fumaric acid in the presence of glycerol and/or various monosaccharides as carbon sources was examined for seventeen different strains of this fungi. These strains were tested in shake-flask cultures on media containing glycerol and seven different carbohydrates, including glucose, fructose, galactose, mannose, xylose, arabinose, and rhamnose. An interesting and applicationally useful phenomenon was observed. This work presents a new approach to the conventional microbiological method of producing fumaric acid. In the presence of 40 g/l glycerol as the sole carbon source, fumaric acid production reached 0.16–6.1 g/l after 192 h. When monosaccharides were used as a single carbon source, the maximum fumaric acid concentration was much higher; for example, 19.8 g/l was achieved when 40 g/l xylose was used. In the co-fermentation of xylose (40 g/l) and glycerol (20 g/l), post-culture broth contained approx. 28.0 g/l of fumaric acid with a process yield of 0.90 g/g after 168 h. The production of fumaric acid by Rhizopus oryzae was also increased in the dual presence of glycerol and monosaccharides like fructose, galactose, and mannose. However, results obtained on glucose-glycerol-based medium did not follow this trend, showing instead complete utilization of glucose with significant glycerol consumption, but unexpectedly low final amounts of fumaric acid and process yields. Understanding how Rhizopus oryzae utilize various carbon sources may provide alternative avenues of fumaric acid fermentation

Effect of Sea Buckthorn (Hippophae rhamnoides L.) Mousse on Properties of Probiotic Yoghurt

The stability of the physico-chemical and sensory characteristics of yoghurts during refrigerated storage is important for industry and the consumer. The aim of the study was to evaluate the nutritional value, microbiological quality, sensory properties, and structure of natural probiotic yoghurts made with the addition of sea buckthorn fruit mousse during refrigerated storage. In this study, we produced natural, probiotic organic yoghurts with the addition of superfoods, i.e., sea buckthorn (Hippophae rhamnoides L.) fruit mousse, using ABT-1 probiotic yoghurt starter culture based on Lactobacillus acidophilus LA-5, Bifidobacterium lactis BB-12, and Streptococcus thermophilus. Physico-chemical (acidity, nutritional value, and structure) as well as microbiological and sensory changes occurring during 21-day refrigerated storage were determined. The yoghurts were characterized by high sanitary and hygienic quality during the whole refrigerated storage. Fourier-Transform Infrared (FTIR) spectra were also used in the analyses of the obtained yoghurt samples. The applied yoghurt additive was visible at the spectral level as an increase in the intensity of the characteristic bands for vibrations related to protein, fat, and polysaccharide structures. Sea buckthorn can be used as a modern and unconventional addition to yoghurts with health-promoting properties. Micrographic studies have shown that the addition of sea buckthorn mousse significantly changes the microstructure of the yoghurt. The structure of sea buckthorn to yoghurt seems to be more susceptible to the influence of damaging factors, which is also confirmed by the FTIR test conducted during the storage