1/2006 - Potravinárstvo

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ktorým sa vydáva hlava Potravinového kódexu Slovenskej republiky upravujúca prídavné látky v potravinách. In Vestník Ministerstva pôdohospodárstva SR. 25. Február 2008, roč. XXXX, č. 4, 2008, s. 1-532. SABATER, VILAR, M., MAAS, F. M., FINK, GREMMELS, J. 1999. Mutagenicity of commercial INTRODUCTION According to Bencini (2001), the most of the sheep milk produced all over the world is transformed into cheeses. For this reason he relates the quality of sheep milk to its capability to be transformed into high quality dairy products and to produce high yields of these products from each liter of milk. Any factor that influence milk composition at the same time affect the yield and quality of final dairy products obtained from ewe’s milk, their chemical composition, texture and flavour. The chemical composition of the milk is a quality factor of relevance for both the consumer and the dairy industry. Although the knowledge of genetic polymorphism of proteins in milk is increasing, there is insufficient knowledge about the effect of genetic variants of milk proteins on the properties of the milk and dairy products and the further research is necessary. Various genetic variants of milk proteins influence the quality of the milk when used, for instance, in cheese making (Abrahamsen et al., 2007). The degree of polymorphism of milk proteins is closely conjoined with the quantitative and qualitative parameters of milk (Czerneková et al., 2004), it means with production yield and composition. <strong>Potravinárstvo</strong> Monascus fermenation products and the role of citrinin contamination. In Mutation Res., roč. 44, 1999, s. 7-16. OU, H. P., WANG, C. R., LAI, L. S. 2009. Thermal degradation kinetics analysis of monacolin K in Monascus – femented products. In LWT – Food Sci. Technol., roč. 42, 2009, s. 292-296. VPLYV GENOTYPOV Β-LAKTOGLOBULÍNU NA ZLOŽENIE BIELKOVINOVÉHO KOMPLEXU A TECHNOLOGICKÉ VLASTNOSTI MLIEKA OVIEC ZOŠĽACHTENÁ VALAŠKA INFLUENCE OF Β-LACTOGLOBULIN GENOTYPES ON THE NITROGEN DISTRIBUTION IN THE TOTAL PROTEIN AND TECHNOLOGICAL PROPERTIES OF MILK FROM THE IMPROVED VALACHIAN SHEEP Anna Michalcová, Zuzana Krupová ABSTRACT The aim of the work was to search genetic polymorphism of β-Lg and its effect on the total milk protein, nitrogen distribution in the total protein and technological properties of milk collected from Slovak Improved Valachian breed sheep. Totally, 166 milk samples were analyzed for whole milk protein, nitrogen distribution in milk, technological properties of milk (pH, calcium content, rennetability, heat stability). The genotypic frequencies at the β-Lg locus, estimated by RLFP- PCR, detected for the Improved Valachian sheep were 0.29 (AA); 0.45 (AB); 0.26 (BB). No statistically significant effect of the genetic variant of β-Lg for the nitrogen distribution in the proteins was found. However, statistically significant differences in the average calcium content (P
cheesemaking properties of milk for A β-Lg. Several reserchers found β-Lg AA genotype to be more suitable for cheese production from the point of better renetability, clotting capability and cheese yield. Milk with β-Lg A allele showed a positive effect on curd formation and curd firming. Curd from milk of β-Lg BB genotype was evaluated as significantly softer (Rampilli et al., 1997). While β-Lg BB genotype is associated with higher milk yield, β-Lg AA and AB genotypes produce milk with higher protein and casein content as well as cheese yield (Garzon a Martinez, 1992). On contrary, Pilla et al. (1995) indicate a positive effect on the B variant β-Lg of clotting time. The highest yield of curd saw Anton et al. (2005) with BB genotype in sheep breeds Awassi and Lacaune. Korman et al. (2002) argue that the productions of whey cheeses were obtained better results with the AB genotypes than in milk from sheep with homozygous genotypes. The goal of the work was study the quality of sheep milk as raw material for the dairy industry, characterize the genetic polymorphism of milk proteins Slovak domestic Improved Valachian sheep breed and to determine an effect of β-lactoglobulin genetic variants on the total milk protein, nitrogen distribution in the total protein and technological properties of milk. MATERIAL AND METHODS Individual milk and blood samples were collected from Improved Valachian sheep (75). The sampling was performed once a month during pasture milking season from May to September. Finally, the effects of lactation stage were evaluated. Individual milk samples were collected at the morning milking and were divided into two parts. The first one (30ml), used for the study of milk composition performed by Milko Scan apparatus was collected into tubes containing preservative agents Acidiol and the second one was only cooled and held at a maximum temperature of 10°C during the transport and was analyzed immediately after arrival to the laboratory with the aim to determine physico-chemical and technological properties of milk. The protein content was stated by infrared technique using a Milko Scan FT 120 (FOSS Electric, Milcom servis, Czech Republic) according to the Slovak technical norm STN 57 05 36 „Determination of milk composition by infrared absorbance analyzator“. True protein nitrogen (TPN) and whey protein nitrogen (WPN) were determined by the method of Cvak et al. (1992). For determination of TPN, 10 grams of whole milk were precipitated with 18% NaCl and 20-25% Almen’s Solution (4g of tannin solubilised in 190 ml of 50% ethanol et 8 ml of 25% acetic acid) and filtered through a nitrogen free KA5 filter (Reachem, Bratislava); three times washed with distilled water and the precipitate retained on the filter was dried at room temperature. The dried precipitate retained on the filter was used for the mineralization stage of the Kjeldal method. For determination of WPN, 20 grams of whole milk were <strong>Potravinárstvo</strong> diluted with distilled water (40 ºC) in the proportion of 1:3.3 (v:v), and precipitated with 10% acetic acid and sodium acetate. A precipitant consisting of the whey proteins passed through a filtrate paper. About 50 ml of the filtrate containing whey proteins was evaporated using a mineralization digestion unit Bloc-Digest 12 (J.P. Selecta, Spain) to obtain a final volume of 15 ml used for nitrogen analyses. The nitrogen content was measured using the Kjeldal method following the EN ISO 8968-1:2001 (2002). The casein content [g.100g -1 ] was calculated as follows: Casein (CN) = true proteins (TP) [g.100g -1 ] – whey proteins (WP) [g.100g -1 ]. The casein number (CNu) was stated according to the following equation: Casein number (CNu) [%] = CN [g.100g -1 ] / TP [g.100g -1 ] x 100. The non-protein nitrogen (NPN) [g.100g -1 ] was expressed as the difference between crude protein nitrogen (CPN) and true protein nitrogen (TPN). Total calcium was stated by the complexometric method of Cvak et al. (1992). One ml of milk was diluted in the distilled water in the proportion of 1:70; 5 ml of 5 M KOH was added in the presence of the fluorexon indicator. The titration was made with 0.01 M Normanal Chelaton III (Reachem, Bratislava). The total calcium content was calculated by the equation present in the method. The pH of milk samples was checked at 20 ºC with the pH meter MS 22 (Laboratory equipments, Praha). Heat stability (alcohol number) was determined by the titration with 96% ethanol according to Gajdůšek (1998). Alcohol number expresses an ethanol consumption of given concentration for fixed bulk of milk (2 cm 3 ) till protein coagulation under the terms of the method. Rennetability was determined by the method of Kažimír a Gemeri (1993). 20 cm 3 of sample was equilibrated at 35 ºC when 1 ml of rennet (power of 1:400) (Chr. Hansen’s hannilase powder, MG 2080, Denmark) was added. The milk was stirred. The time till the creation of first curd flakes was measured in seconds. Genotyping of β-lactoglobulin by Restriction Fragment Length Polymorphism- Polymerase Chain Reaction (RFLP-PCR) Genetic polymorphism of β-lactoglobulin gene (alleles A and B) was analyzed by the RLFP-PCR method by Anton et al. (1999) in the laboratory of Department of Botany and Genetics, Constantine the Philosopher University in Nitra. The following primers were used for the amplification of DNA: LGB1 forward primer: (5'- CTTCCCACCCCCAGAG TGCAAC-3') LGB2 reverse primer: (5'- TGGGGAGTGGGGGTTC CATGTT-3'). PCR reaction was performed in a 20-µl reaction mixture containing 1x PCR reaction buffer, 2 mM MgCl2, 0.2 mM dNTP mix, 0.5 µM primers, 0.5 U Taq DNA polymerase (Invitrogen) and 1 µl of DNA sample (± 100 ng) in thermocycler Primus. The PCR conditions were applied as follows: 94°C 4 min., 31x (94°C 30 s, 65°C 30 s, 72°C 30 s) and 72°C 10 min. The length of the PCR product was verified on the 1% agarose gel. Finally, a 217 bp DNA fragment was amplified. ročník 4 59 1/2010
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Vedecký èasopis pre potravinárst
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ÚVOD Pšenica je celosvetovo jedna
Page 5 and 6:
oqueforti (2), P. carneum (1), P. c
Page 7 and 8:
aminokyselín a ión-párového či
Page 9 and 10: Tab. 2b: pokračovanie. Literatura
Page 11 and 12: pestovaná aj v Maďarsku, Česku,
Page 13 and 14: Pri ostatných hodnotených ukazova
Page 15 and 16: Potravinárstvo positive significan
Page 17 and 18: REFERENCE AYADI, M., CAJA, G., SUCH
Page 19 and 20: zastúpení a stanoviť optimálny
Page 21 and 22: ZÁVER Jačmeň nahý sa vyznačuje
Page 23 and 24: Bielkovinové frakcie (albumíny, g
Page 25 and 26: detegovaná podjednotka 2+12, ktor
Page 27 and 28: PAYNE, P. I., NIGHTINGALE, M. A., K
Page 29 and 30: different copies of integrated gene
Page 31 and 32: INTRODUCTION Flaxseed and walnut oi
Page 33 and 34: Table 1. Characteristics of fresh c
Page 35 and 36: ∆E 18 16 14 12 10 8 6 4 2 0 Potra
Page 37 and 38: ÚVOD Mlieko je vzhľadom na svoje
Page 39 and 40: log K T J .m l -1 Obrázok 2: Prež
Page 41 and 42: ÚVOD Kvasinky a vláknité huby s
Page 43 and 44: Okrem uvedených metabolitov môžu
Page 45 and 46: Obbr. 2: Vplyv kkultúry Lactobbaci
Page 47 and 48: ÚVOD V súčasnosti medzi najdôle
Page 49 and 50: Index klíčenia Index klíčenia 1
Page 51 and 52: ZÁVER Pozberové dozrievanie (dorm
Page 53 and 54: Potravinárstvo Table 1: The summar
Page 55 and 56: period. Żyw. Człow. Metab., 2007,
Page 57 and 58: pH vzoriek bol tiež zaznamenaný.
Page 59: DISKUSIA Testovanie vplyvu tepla a
Page 63 and 64: the effect of the lactation period
Page 65 and 66: CONCLUSION We have confirmed the in
Page 67 and 68: 15 % sušiny (Dawczynski et al., 20
Page 69 and 70: ylo do filtračních sáčků (F 57
Page 71 and 72: metodami in vitro, kdy je možné s
Page 73 and 74: parametry byly stanoveny jednak met
Page 75 and 76: ČURDA, L., KUKAČKOVÁ, O., NOVOTN
Page 77 and 78: Zdroj žiarenia: γ-žiarenie z Co
Page 79 and 80: celková chutnosť vôňa doznievan
Page 81 and 82: predstavuje len veľmi miernu hladi
Page 83 and 84: prítomnosti kvasiniek a plesní, n
Page 85 and 86: Potravinárstvo Tab. 1: (pokračova
Page 87 and 88: multifunctional metabolic pathway i
Page 89 and 90: Kolín a naopak najnižšie hodnoty
Page 91 and 92: ZÁVER Analýza získanej biomasy k
Page 93 and 94: produkciu potravín živočíšneho
Page 95 and 96: Vypočítané hodnoty iónových po
Page 97 and 98: ÚVOD Rod Nigrospora Zimmerm. podľ
Page 99 and 100: Potravinárstvo Obrázok 1: Nigrosp
Page 101 and 102: LITERATÚRA CLEAR, R. M., PATRICK,
Page 103 and 104: vlastnosť pri priemyselne vyrobeno
Page 105 and 106: Potravinárstvo Obrázok 1: Závisl
Page 107 and 108: práce a typ múky sú faktory ktor
Page 109 and 110: ICC STANDARD NO. 106/2, 1984. Worki
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ZUZANA BARBORÁKOVÁ, SOŇA FELŠÖ
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