Caracterização físico-química de queijo prato por espectroscopia no infravermelho e regressão de mínimos quadrados parciais

In this work an analytical methodology for the determination of relevant physicochemical parameters of prato cheese is reported, using infrared spectroscopy (DRIFT) and partial least squares regression (PLS). Several multivariate models were developed, using different spectral regions and preprocessing routines. In general, good precision and accuracy was observed for all studied parameters (fat, protein, moisture, total solids, ashes and pH) with standard deviations comparable with those provided by the conventional methodologies. The implantation of this multivariate routine involves significant analytical advantages, including reduction of cost and time of analysis, minimization of human errors, and elimination of chemical residues.

Utilização de resíduos agroindustriais para a produção de proteases pelo termofílico Bacillus sp em fermentação submersa: otimização do meio de cultura usando a técnica de planejamento experimental

Thermophilic Bacillus sp. SMIA-2, produced protease when grown on apple pectic, whey protein and corn step liquor medium, whose concentration was varied from 3 to 10 gL-1, according to the central composite design 2³. The experiments were conducted in shaker, at 50 °C, 150 rpm and initial pH 6.5. The results revealed that the culture medium affected both, cell growth and enzyme production. After graphical and numerical optimization procedure, the enzyme production reached its maximum value at 30 h fermentation, reaching, approximately, 70 U protein mg-1, suggesting that this process was partially associated to the growth.

Implementação de um método robusto para o controle fiscal de umidade em queijo minas artesanal. Abordagem metrológica multivariada

This study developed and validated a method for moisture determination in artisanal Minas cheese, using near-infrared spectroscopy and partial-least-squares. The model robustness was assured by broad sample diversity, real conditions of routine analysis, variable selection, outlier detection and analytical validation. The model was built from 28.5-55.5% w/w, with a root-mean-square-error-of-prediction of 1.6%. After its adoption, the method stability was confirmed over a period of two years through the development of a control chart. Besides this specific method, the present study sought to provide an example multivariate metrological methodology with potential for application in several areas, including new aspects, such as more stringent evaluation of the linearity of multivariate methods.

Adsorção de alfa-lactalbumina do soro de leite em hidroxiapatita: efeito do pH e da temperatura e análise termodinâmica

The nutritional and functional benefits offered by whey protein α-lactalbumin justify the great interest in its manufacture in large quantities at a high purity level. Hydroxyapatite is a calcium phosphate material able to adsorb proteins and can be synthesized at low production cost. Therefore, this work evaluated the adsorption of α-lactalbumin on hydroxyapatite using solid-liquid phase equilibrium data reported as adsorption isotherms. Van't Hoff's thermodynamics analysis showed that the adsorption process is entropically driven.

PARTIÇÃO DE PROTEÍNAS DE SORO DE LEITE EM SISTEMAS AQUOSOS BIFÁSICOS BASEADOS EM LÍQUIDOS IÔNICOS

In this work, we used an aqueous two-phase system (ATPS) consisting of the ionic liquid [C4mim][Cl] and the salt K2HPO4 to partition α-lactalbumin, β-lactoglobulin, and lactoferrin whey proteins. Extraction efficiency values above 87% indicate that the proteins primarily migrated to the ionic liquid-rich phase (top phase). Partition coefficient values ranged from 6.17 to 8.93 for a-lactalbumin, from 22.80 to 34.55 for β-lactoglobulin, and from 26.46 to 40.06 for lactoferrin. Therefore, the saline ATPS with the ionic liquid examined in this study can be considered to be a promising alternative for extracting whey proteins.

Tavoitevarastoarvojen määrittäminen uusille tuotteille - case: päivittäistavarakaupan yritys

Tämän tutkielman tarkoituksena oli löytää keinoja uusien tuotteiden tavoitevarastoarvojen määrittämisen helpottamiseksi case-yrityksessä. Ongelma on seurausta siitä, ettei uusille tuotteille ole saatavissa kysyntädataa. Oikeelliset tavoitevarastoarvot on tärkeitä case-yritykselle hävikin minimoimisen ja erityisesti asiakastyytyväisyyden vuoksi. Tutkittavaa aihetta lähestyttiin päivittäistavarakaupan strategisten menestystekijöiden sekä varastonhallinnan kautta. Teoriaosuuden pohjalta toteutettiin empiirinen osio, jossa etsittiin case-yrityksen kahden tuoteryhmän kysyntää selittäviä tekijöitä paneeliregression avulla. Ensin kuitenkin tutkittiin tuoteryhmien yleistä kysynnän rakennetta erilaisten kysyntäkuvaajien sekä korrelaatiomatriisien avulla. Tavoitevarastoarvoon eniten vaikuttava tekijä on kysyntä. Brändi ja hinta muodostuivat puolestaan vahvimmiksi kysyntää määrittäviksi muuttujiksi. Kysyntää arvioitaessa muut sitä nostavat muuttujat tulee aina miettiä tapauskohtaisesti. Mehukeitoilla kysyntää nostivat eniten vahva brändi ja suuri pakkauskoko. Juustoraasteilla puolestaan alhainen hinta ja pieni pakkauskoko olivat keskeisimmät myyntiin vaikuttavat tekijät. Tuoteryhmien muut kysyntää nostavat ominaisuudet olivat samoja, kuin tuoteryhmän suosituimmilla tuotteilla.

Passive immunity transfer and serum constituents of crossbred calves

Passive immunity transfer (PIT) evaluation is an essential tool for the maintenance of healthy calves during the first months of life. Since lactation number and breed have been proven to influence immunoglobulin levels in colostrum, the aim of this study was to evaluate PIT from primiparous and multiparous Canchim cows to their calves. Blood samples were collected from the calves before colostrum intake and 1, 2, 7, 15 and 30 days thereafter, while colostrum samples from the cows were taken immediately after parturition. Activities of gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and concentrations of total protein, albumin, globulins, immunoglobulin A (IgA), immunoglobulin G (IgG), total and ionized calcium, inorganic phosphorus, magnesium, sodium and potassium were evaluated in calves' serum and activities of GGT and ALP and concentrations of total protein, IgA and IgG were assessed in cow's colostrum whey. Immunoglobulins concentrations were evaluated by electrophoresis in polyacrylamide gels. Serum biochemistry evaluations revealed an increase in gamma-glutamyl transferase and alkaline phosphatase activities and in total protein, globulins, immunoglobulin A and immunoglobulin G levels in calves' serum after colostrum intake. Only total protein and light chain immunoglobulin G levels in colostrum whey were affected by the cows' lactation number. Phosphorus and magnesium levels in blood serum increased after colostrum intake, while sodium and potassium levels oscillated in the experimental period. PIT was influenced by the cows' lactation number but was efficient in both groups.

Maidon ja heran mikrosuodatus

Työssä selvitettiin uudenaikaisten polymeerikalvojen soveltuvuutta maidon sekä heran mikrosuodatukseen. Kirjallisessa osassa perehdyttiin maidon ja heran koostumuksiin, mikrobikantoihin sekä erilaisiin maidon sekä heran rasvanpoisto- ja puhdistusmenetelmiin. Tämän lisäksi käsiteltiin mikrosuodatusmenetelmiä sekä niiden käyttöä heran ja maidon käsittelyssä meijeriteollisuudessa. Kokeellisessa osassa verrattiin kahdella eri suodatuslaitteistolla keraami- ja polymeerikalvojen suodatusominaisuuksia separoidun raakamaidon sekä heran poikkivirtausmikrosuodatuksessa. Tavoitteena oli erottaa suodatettavista liuoksista mikrobit sekä jäännösrasva ja tuottaa puhdasta, proteiinipitoista maitoa / heraa. Koeajoissa otetuista näytteistä analysoitiin ainesosakoostumus sekä mikrobipitoisuudet. Tuloksista määritettiin retentioarvot ja näiden perusteella vertailtiin polymeeri- ja keraamikalvojen erotustehokkuutta. Lisäksi kalvojen toimivuutta arvioitiin vuoarvojen avulla. Raakamaidon suodatuksissa polymeerikalvot pidättivät täydellisesti tai lähes täydellisesti jäännösrasvan ja mikrobit, mutta myös kaseiiniproteiinin. Tästä syystä yksikään polymeerikalvoista ei sovellu puhtaan maidon suodatukseen. Keraamikalvot soveltuvat tähän selkeästi paremmin ja yksikään toinen testatuista kalvoista ei päässyt samalle tasolle meijeriteollisuudessa jo käytössä olevan Membralox 1,4 μm -keraamikalvon kanssa. Heran suodatuksissa polymeerikalvot pidättivät täydellisesti tai lähes täydellisesti rasvan ja mikrobit, mutta keraamikalvo päästi huomattavasti enemmän haluttuja proteiineja permeaattiin. Membralox 0,8 μm -keraamikalvo pidätti täydellisesti mikrobit, mutta päästi jonkin verran jäännösrasvaa permeaattiin. Näin ollen kalvovalinta on kompromissi permeaatin puhtauden ja proteiinin saannon välillä. Keraamikalvojen vuohäviöt olivat merkittävästi pienemmät kuin polymeerikalvoilla molempien syöttöliuosten kanssa. Lisäksi keraamikalvojen puhdistus oli huomattavasti nopeampaa ja helpompaa. Tästä syystä keraamiset kalvot soveltuvat polymeerisiä paremmin maidon ja heran mikrosuodatukseen.

Pre- and postnatal nutrition – target for allergy risk reduction

A rapid increase in allergic diseases in Western societies has led to the conclusion that our modern lifestyle is a risk factor for immune dysregulation. Potential culprits and benefactors are searched among early dietary and microbial exposures, which may act to program later allergic disease. The aim of this thesis was to investigate the role of early maternal and child nutrition in reducing the risk of child allergy. The study population comprised of 256 mother – child pairs from families with a history of allergy participating in a randomized controlled dietary counseling and probiotic intervention (Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12) study from early pregnancy onwards. The dietary counseling aimed for a diet complying with dietary recommendations for pregnant and lactating women, with special attention to fat quality. Maternal dietary counseling was reflected in cord blood fatty acids suggesting better essential fatty acid status in infants in the counseling group. Dietary counseling with probiotics or placebo had no effect on child allergy risk, but associations between maternal diet during pregnancy and breastfeeding and child allergic outcomes were found in secondary analyses. During pregnancy, milk intake was related to decreased and cheese intake to increased risk of child atopic eczema. During breastfeeding, intake of vitamin C was related to increased risk of asthma and intake of egg was related to decreased risk of atopic eczema. The timing of introduction of complementary foods to infant’s diet was not associated with risk of atopic eczema, when adjusted with parental opinion of child allergic symptoms (i.e., potential reverse causality). In conclusion, the results demonstrate that infant fatty acid supply can be modified via maternal dietary changes. In addition, interesting associations of maternal diet with child allergy risk were discovered. However, no difference in the incidence of allergic diseases with dietary counseling was observed. This suggests that more potent dietary interventions might be necessitated to induce clinical risk reduction of allergy. Highrisk families can safely adhere to dietary recommendations for pregnant and lactating women, and the results support the current conception that no additional benefit is gained with delaying introduction of complementary feeding.

Protein turnover, amino acid requirements and recommendations for athletes and active populations

Skeletal muscle is the major deposit of protein molecules. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. Stable isotopic tracers (13C-lysine, 15N-glycine, ²H5-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g·kg-1·day-1 compared to 0.8 g·kg-1·day-1 in resting individuals. Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. As suggested in several publications, a bolus of 15-20 g protein (from skimmed milk or whey proteins) and carbohydrate (± 30 g maltodextrine) drinks is needed immediately after stopping exercise to stimulate muscle protein and tendon collagen turnover within 1 h.

Free and total GMP (glycomacropeptide) contents of milk during bovine lactation

Individual milk samples taken every two weeks from parturition to the end of lactation from 34 animals of three different herds and breeds were analyzed for free-GMP. A milk pool of each herd was analyzed for free and total GMP (released from k-casein by the action of rennin) and the data were correlated with sanitary conditions of animal and udder, phase of lactation and milk production. Most udder problems were concentrated near parturition, with few and spaced occurrences of clinical mastitis. The Californian Mastitis Test (CMT) results showed oscillations compatible with the phases of lactation period and environmental conditions. The widest variations in free-GMP occurred as a function of lactation period and as a consequence of clinical or subclinical mastitis. Higher levels were observed at the beginning of lactation (5.87mg L-1 of sialic acid), becoming normal with mean values of about 3.30mg L-1 at the end of the second month, and increasing again during the final third of lactation. On average, the same trends were observed for total GMP released by commercial rennet, beginning with slightly high values (35.59mg L-1), becoming normal by the sixth month with values close to 27.15mg L-1, and rising gradually up to the end of lactation, with 58.35mg L-1 of sialic acid. These results prove to be useful for the correct interpretation of tests applied to milk selection with respect to proteolytic status or even to restrain frauds by the addition of whey to milk.

Potential of quixaba (Sideroxylon obtusifolium) latex as a milk-clotting agent

There are several obstacles to the use of chymosin in cheese production. Consequently, plant proteases have been studied as possible rennet substitutes, but most of these enzymes are unsuitable for the manufacture of cheese. The aim of this study was to evaluate the potential of latex from Sideroxylon obtusifolium as a source of milk-clotting proteases and to partially characterize the enzyme. The enzyme extract showed high protease and coagulant activities, with an optimal pH of 8.0 and temperature of 55 °C. The enzyme was stable in wide ranges of temperature and pH. Its activity was not affected by any metal ions tested; but was inhibited by phenylmethanesulfonyl fluoride and pepstatin. For the coagulant activity, the optimal concentration of CaCl2 was 10 µmol L- 1. Polyacrylamide gel electrophoresis showed four bands, with molecular weights between 17 and 64 kDa. These results indicate that the enzyme can be applied to the cheese industry.

Peptide separation of commercial fermented milk during refrigerated storage

Milk is an important source of bioactive compounds. Many of these compounds are released during fermentation and refrigerated storage. The aim of this study was to determine the release of peptides by lactic acid bacteria in commercial fermented milk during refrigerated storage. The size and profile of peptides were analyzed by polyacrylamide gel electrophoresis and sizeexclusion HPLC. During electrophoresis, it was observed that the peptides were released from caseins, whereas β-lactoglobulin was the whey protein with the highest degradation. HPLC analysis confirmed the pattern of peptide formation observed in electrophoresis. Two fractions lower than 2 kDa with aromatic amino acids in their structure were separated. These results were consistent with those reported for structures of peptides with antihypertensive activity. Therefore, the presence of aromatic amino acids in the peptide fractions obtained increases the likelihood of finding peptides with such activity in refrigerated commercial fermented milk. In conclusion, during cold storage, peptides with different molecular weights are released and accumulated. This could be due to the action of proteinases and peptidases of the proteolytic system in lactic acid bacteria.

Labneh with probiotic properties produced from kefir: development and sensory evaluation

The labneh or labaneh is a popular fermented milk in the Middle East. Another fermented product that deserves special mention is kefir since it has probiotic activity and unique sensory, nutritional, and therapeutic properties. The aim of the present study was to develop a functional probiotic labneh using kefir as a fermenting agent and to perform a sensory analysis of the obtained product. Kefir was obtained by growing grains in pasteurized milk. Samples of skimmed and whole labneh were prepared from the inoculation of 5% kefir milk (skimmed/whole) at 28 ºC for 24h, followed by cooling (12-18h) and whey drainage (12-24h), both at 4 ºC. Sensory analysis was performed with 70 untrained panelists using a 9-point scale hedonic in the acceptance tests. The paired t-test was used to compare the differences between the means of the scores obtained, with the significance level of 5%. The labneh prepared showed good acceptance by the judges, and the whole labneh samples had the highest scores in the acceptance test. Further studies on the analysis of microbiological viability, nutritional composition, and determination of shelf life, also to improve acceptability of the low-fat version of the product, are needed.

Comparison between aroma compounds in wines from four Vitis vinifera grape varieties grown in different shoot positions

The aroma characteristics of wines from four Vitis vinifera grape varieties (‘Cabernet sauvignon’, ‘Merlot’, ‘Chardonnay’, and ‘Italian Riesling’) grown in three shoot positions were evaluated by HS-SPME-GC/MS. In this study, the numerous significant differences found in most of the aromatic compounds influence of different shoot positions on the quality of wine. The results showed that the middle shoot position increased significantly the aroma concentration in the majority of wines investigated. The volatile components showing the greatest differences in the wines of different cultivars were aldehydes and terpenes. 8 and 11 compounds were found and quantified (OAVs>1) in the two red wines and white wines at concentrations higher than their corresponding odor thresholds, respectively; and therefore they significantly contributed to the wine aromas. According to their OAVs, fruity, floral, cheese and fatty aroma strongly influenced the characteristics of the four monovarietal wines, while the two white wines showed the green and fresh aroma characteristics. These results are related to the different microclimate of the canopies of the different shoot positions and varieties. They suggest that proper elevating the fruiting zones could improve the accumulation of aroma compounds in wines from the different varieties. On the other hand, grapevines trained to systems with uniform fruiting zones could improve the quality of wine.