Hydroxymethylfurfural content, diastase activity and colour of multifloral honeys in relation to origin and storage time

Celem pracy było porównanie jakości miodów wielokwiatowych dostępnych na polskim rynku detalicznym w zależności od ich pochodzenia (krajowe vs. zagraniczne) oraz czasu przechowywania (przed lub po upływie daty minimalnej trwałości). Badaniami objęto 24 próby miodów wielokwiatowych, w tym krajowe (tj. niekonfekcjonowane zakupione na bazarach bezpośrednio od pszczelarzy i nabyte w detalicznej sieci handlowej) i zagraniczne (z krajów członkowskich Unii Europejskiej i spoza niej) zakupione w hipermarketach. Dodatkowo oceniono 5 prób zakupionych wcześniej miodów, dla których minęła już data ich minimalnej trwałości. W miodach oznaczono zawartość 5-hydroksymetylofurfuralu (5-HMF), wartość liczby diastazowej (LD) oraz barwę wg CIE L*a*b*. W świeżych miodach wielokwiatowych (niezależnie od pochodzenia) zawartość 5-HMF wahała się od 1,17 do 18,54 mg·kg-1 , a wartość LD od 8,36 do 34,88. Tym samym wszystkie próby spełniały ustawowe wymagania (8 wg skali Schade dla LD). Wykazano istotne (P≤0,01) obniżenie jakości miodów po upływie daty minimalnej trwałości. Przeciętna zawartość HMF (93,87 mg·kg-1) była dwukrotnie większa niż wartość dopuszczalna, podobnie średnia wartość LD (6,45) była niższa od przyjętego limitu. Wykazano istotne różnice (P≤0,01) pomiędzy średnimi wartościami wszystkich parametrów barwy miodów w zależności od czasu przechowywania. Barwa miodów po upływie daty minimalnej trwałości była istotnie ciemniejsza i o mniejszym nasyceniu (L*=43,18 i C*=21,23) w porównaniu do miodów świeżych (L*=62,11 i C*=32,66).The aim of the study was to compare the quality of multifloral honeys in relation to origin (domestic vs. foreign), and storage time (before vs. after the date of minimum durability) available on the Polish retail market. The study was conducted on 24 samples of multifloral honey, including domestic ones (i.e. originated directly from beekeepers in open-air markets, or purchased in a retail chain), and foreign (i.e. from inside or outside the EU) bought in hypermarkets. In addition, the study comprised 5 samples of honey after the date of minimum durability. The content of hydroxymethylfurfural (5-HMF), diastase number (DN) and colour according to CIE L*a*b* were determined in honeys. In the fresh multifloral honeys (irrespective of origin) the content of 5-HMF ranged from 1.17 to 18.54 mg·kg-1, and DN ranged from 8.36 to 34.88. Thus all samples met the legal requirements (5-HMF<40 mg·kg-1 and DN<8 on the Schade scale). Significant (P≤0.01) deterioration in the quality of the honey was noted after the date of minimum durability. The mean HMF content (93.87 mg·kg-1) was twice as high as the acceptable value, and the mean DN (6.45) was lower than the accepted limit. Significant differences (P≤0.01) were noted between mean values for all colour coordinates considering the date of minimum durability. The colour of the honey after the date of minimum durability was significantly darker and had lower saturation (L*=43.18 and C*=21.23) than the fresh honey (L*=62.11 and C*=32.66)

Nutritional value and coagulation properties of milk from local cow breeds, including the selected macro- and micronutrients and trace elements

Cilj ovog istraživanja bio je odrediti prehrambenu vrijednost mlijeka na osnovu kemijskog sastava i sadržaja odabranih mineralnih tvari, te sposobnost koagulacije sirovog mlijeka izvornih pasmina - poljsko crvenih i bijelo-crnih, lokalno uzgojenih simentalskih krava, uzimajući u obzir utjecaj sezone. Istraživanje je provedeno na ukupno 418 uzoraka mlijeka uzetih tijekom proljeća/ljeta (travanj do rujan) odnosno jeseni/zime (listopad do ožujak). Uzorcima su određivani kemijski sastav, energijska vrijednost, sposobnost koagulacije (RCT - vrijeme zgrušavanja, A30 - čvrstoća gruša, K20 - vrijeme potrebno za postizanje odgovarajuće čvrstoće gruša), prinos sira te sadržaj K, Na, Ca, Mg, Zn, Fe, Mn, Cu, Ni i Co. Također je određeno u kojem postotku konzumacija 250 mL testiranih uzoraka mlijeka pokriva dnevni preporučeni unos Ca i Mg za djecu, adolescente i odrasle. Mlijeko pasmine poljsko crveno sadržavalo je najviše koncentracije osnovnih nutrijenata (1 kg mlijeka imalo je energijsku vrijednost od 823,98 kcal) i imalo je najbolju sposobnost koagulacije mlijeka (najkraće vrijeme zgrušavanja (16:09 min, p≤0,01) i najčvršći gruš (30,74 mm)). Ovaj uzorak mlijeka imao je bolji nutritivni profil budući da je sadržavao najviši postotak preporučenih dnevnih unosa za Ca i Mg. Sirovo mlijeko dobiveno u sezoni ispaše imalo je bolje parametre sposobnosti koagulacije. Sadržaj mineralnih tvari nije bio uvjetovan pasminom ni sezonom proizvodnje. To je vjerojatno posljedica većih udjela ovih nutrijenata u stočnoj hrani, što je povezano s njihovim sadržajem u tlu kao i sa stupnjem fertiliziacije.The aim of the study was to assess the nutritional value of milk based on its chemical composition and content of selected minerals and to determine the coagulation properties of raw milk from native Polish breeds, i.e. the Polish Red and the White-backed, as well as locally raised Simmental cows, taking into account the production season. The research material consisted of 418 milk samples taken during the spring/summer season (April to September) and autumn/winter season (October to March). The following parameters were determined in the samples: chemical composition, energetic value, coagulation properties (RCT - rennet clotting time, A30 - curd firmness, K20 - curd firming time), cheese yield, and content of K, Na, Ca, Mg, Zn, Fe, Mn, Cu, Ni and Co. The percentage of the daily allowance for Ca and Mg in children, adolescents and adults from 250 mL of milk was determined. The milk of Polish Red cows had the highest concentration of basic nutrients (1 kg of milk provided 823.98 kcal) and the best coagulation parameters (the shortest clotting time (16:09 min, p≤0.01) and firmest curd (30.74 mm). This milk had a more beneficial nutritional profile, as it contained the highest percentage of the recommended daily allowances of Ca and Mg among all groups. The raw milk obtained in the pasture season showed more favourable coagulation properties. The content of minerals in milk is not clearly determined by the cow breed or the season. It is probably due to the higher levels of these nutrients in the feed, which in turn results from their content in the soil and the degree of fertilization

The Effect of Humic Mineral Substances from Oxyhumolite on the Coagulation Properties and Mineral Content of the Milk of Holstein-Friesian Cows

The study was conducted to determine the effect of humic mineral substances from oxyhumolite added to the diet of Holstein-Friesian cows on the coagulation properties, proximate chemical composition, and mineral profile of milk. The experiment was conducted on 64 cows divided into two groups of 32 each, control (CON) and experimental (H). The group H cows received the humic mineral substances as feed additive, containing 65% humic acids, for 60 days (100 g cow/day). Milk samples were collected twice, after 30 and 60 days. After 30 days no significant changes were observed in the chemical composition, somatic cell count (SCC), mineral content (except potassium), or curd texture parameters. However, the coagulation properties improved. The milk from group H after both 30 and 60 days coagulated significantly (15%) faster on average (p &lt; 0.05), and the curd was about 36% and 28% firmer after 30 and 60 days, respectively (p &lt; 0.05). After 60 days there was an increase in the content of fat (by 0.27 p.p.; p = 0.041), protein (by 0.14 p.p.; p = 0.012), and casein (by 0.12 p.p.; p = 0.029). SCC decreased by 20% (p = 0.023). The curds were significantly harder and less fracturable compared to the control. Calcium and iron content increased as well. The results indicate that humic mineral substances from oxyhumolite in the diet of cows can improve the suitability of milk for cheese production

Relationships between the Content of Phenolic Compounds and the Antioxidant Activity of Polish Honey Varieties as a Tool for Botanical Discrimination

The study compared the content of eight phenolic acids and four flavonoids and the antioxidant activity of six Polish varietal honeys. An attempt was also made to determine the correlations between the antioxidant parameters of the honeys and their polyphenol profile using principal component analysis. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (ABTS) and reduction capacity (FRAP) were determined spectrophotometrically, and the phenolic compounds were determined using high-performance liquid chromatography (HPLC). The buckwheat honeys showed the strongest antioxidant activity, most likely because they had the highest concentrations of total phenols, total flavonoids, p-hydroxybenzoic acid, caffeic acid, p-coumaric acid, vanillic acid and chrysin. The principal component analysis (PCA) of the data showed significant relationships between the botanic origin of the honey, the total content of phenolic compounds and flavonoids and the antioxidant activity of the six Polish varietal honeys. The strongest, significant correlations were shown for parameters of antioxidant activity and TPC, TFC, p-hydroxybenzoic acid, caffeic acid and p-coumaric acid. Analysis of four principal components (explaining 86.9% of the total variance), as a classification tool, confirmed the distinctiveness of the Polish honeys in terms of their antioxidant activity and content of phenolic compounds

Residues of Pesticides and Heavy Metals in Polish Varietal Honey

The levels of chemical pollutants were determined in 30 samples of varietal honey from southeastern Poland, including 223 pesticides (insecticides, herbicides, fungicides, acaricides, plant growth regulators, and veterinary drugs) and 5 heavy metals (Pb, Cd, Hg, Cu, and Zn). In 10% of the samples, no pesticide residues were found. The most frequently identified pesticides were thiacloprid (90% of the samples, max 0.337 mg/kg), acetamiprid (86.6%, max 0.061 mg/kg), carbendazim (60%, max 0.049 mg/kg), DMF (56.6%, max 0.038 mg/kg), total amitraz (53.3%, max 0.075 mg/kg), thiamethoxam (26.6%, max 0.004 mg/kg), thiacloprid-amide (13.3%, max 0.012 mg/kg), dimethoate (10%, max 0.003 mg/kg), azoxystrobin (10%, max 0.002 mg/kg), tebuconazole (6.66%, max 0.002 mg/kg), and boscalid (3.33%, max 0.001 mg/kg). The acceptable limits for the compounds were not exceeded in any sample. The Pb content ranged between 0.044 and 0.081 mg/kg. The concentration of Hg and Cd did not exceed 5.0 &micro;g/kg and 0.02 mg/kg, respectively. The honey variety significantly (p &lt; 0.01) influenced the content of Cu, which ranged from 0.504 (rapeseed honey) to 1.201 mg/kg (buckwheat). A similar tendency (p &gt; 0.05) was observed for the Zn content, which ranged from 0.657 mg/kg (linden) to 2.694 mg/kg (buckwheat). Honey produced in southeastern Poland was shown to be safe for human consumption

Relationships Linking the Colour and Elemental Concentrations of Blossom Honeys with Their Antioxidant Activity: A Chemometric Approach

The antioxidant activity of honey depends on the botanical origin, which also determines their physicochemical properties. In this study, a multivariate analysis was used to confirm potential relationships between the antioxidant properties and colour parameters, as well as the content of seven elements in five types of artisanal honey (rapeseed, buckwheat, linden, black locust, and multifloral). The type of honey was found to significantly influence most of its physicochemical properties, colour parameters, and the content of potassium, manganese and copper. Antioxidant parameters were shown to be significantly positively correlated with redness and concentrations of copper and manganese, but negatively correlated with the hue angle and lightness. The principal component analysis confirmed that the darkest buckwheat honey had the highest antioxidant activity in combination with its specific colour parameters and content of antioxidant minerals (manganese, copper and zinc). The level of these parameters can be potentially used for the identification of buckwheat honey

Effect of Milk Thistle (Silybum marianum) Supplementation on Pork Offal Quality

The aim of the study was to determine the effect of milk thistle supplementation of fattener pig feeds on physical and chemical properties of pork offal. The experiments were conducted on 60 fatteners (group C&mdash;control (30 pigs) and group E&mdash;experimental (30 pigs)). The experimental group was supplemented with ground milk thistle (Silybum marianum) at 7 g/kg feed. The offal (tongues, kidneys, hearts, lungs and livers) was analyzed for weight, pH, WHC, water, protein, fat, energy value, fatty acid profile and content of major and trace elements. The present study shows that milk thistle added to fattener pig diets increased pH45 and pH24 values in most of the analyzed offal and significantly (p &le; 0.01) decreased the weight of heart and lungs and increased the weight of liver and kidneys. Hearts, lungs and kidneys of the experimental group contained more fat and the liver less, than the same offal of the control group. As regards the content of elements, the dietary supplement most often had an effect on the heart and lungs. In general, milk thistle supplemented in fattener diets had modified the physical parameters and chemical composition of the analyzed products

Antioxidant Properties and Proximate Composition of Different Tissues of European Beaver

The chemical composition, content of cholesterol, retinol and &alpha;-tocopherol, and the total antioxidant capacity of different tissues from wild beavers were investigated. The total phenolic contents and free radical scavenging activity (DPPH and ABTS assays) were analysed spectrophotometrically, and fat-soluble vitamins were quantified using high-performance liquid chromatography. The type of tissue (skeletal muscle from loin and hind leg vs. adipose tissue from subcutaneous fat and tail) significantly affected content of all chemical components. The concentration of cholesterol was not related to total fat content. The retinol and &alpha;-tocopherol contents (&micro;g/100 g) were significantly higher in the tail (13.0 and 391.2) and subcutaneous fat (12.2 and 371.3) compared to skeletal muscles (as an average 9.1 and 361.4). Among all tissues the tail showed significantly the highest values of DPPH (3.07 mM TE/100 g), ABTS (3.33 mM TE/100 g), and total phenolics (TPC, 543.7 mg GAE/100 g). The concentration of retinol was positively correlated with &alpha;-tocopherol (0.748, p &lt; 0.001), and both vitamins were very strongly correlated with DPPH (0.858 and 0.886, p &lt; 0.001), ABTS (0.894 and 0.851, p &lt; 0.001), and TPC (0.666 and 0.913, p &lt; 0.001). The principal component analysis proved that moisture, ash, and protein contents were representative for skeletal muscles, whereas, retinol, &alpha;-tocopherol, ABTS and DPPH accurately described the antioxidant capacity of tissue from the tail

Application of FTIR spectroscopy for analysis of the quality of honey

Every kind of honey is a very precious natural product which is made by Mellifera bees species. The chemical composition of honey depends on its origin or mode of production. Honey consists essentially of different sugars, predominantly fructose and glucose. There are also non – sugar ingredients like proteins and amino acids, as well as some kind of enzymes, such as: invertase, amylase, glucose oxidase, catalase and phosphatase. The fact that honey is one of the oldest medicine known worldwide is remarkable. Scientists all over the world have been trying to improve analytical methods as well as to implement new ones in order to reaffirm the high quality of honey the benefits of which may be distracted or disturbed. There are many methods and popular analytical techniques, including as follows: mass spectroscopy and molecular spectroscopy (especially FTIR spectroscopy). The infrared spectroscopy technique is one of the most common analytical methods which are used to analyse honey nowadays. The main aim of the task was to use ATR-FTIR infrared spectroscopy to compare selected honey samples as well as typical sequences coming out from certain functional groups in the analysed samples