Investigation of the shelf life of fruit yogurts as a function of the treatment of flavoring substances

Milk and dairy products represent one of the foundations of the human diet because of their valuable ingredients and pleasant sensory properties. The aim of our research was to investigate how different heat treatment processes (microwave irradiation, drying) affect the shelf life of dairy products (yogurt) from a microbiological point of view. In the course of our measurements, the effects of the different heat treatment parameters of the flavoring substances used in the production of the products (apples, bananas) on the microbiological properties of the products and, thus, on their shelf life were investigated. In our experiments, conventional drying (55 °C, 24 hours) and microwave irradiation technology (800 W, 55 °C, 10 min) were used as treatment forms of the additives. Comparisons were made in terms of microbiological parameters (total viable count, yeast/mold count and E. coli/coliform count). Based on our results, we believe that the drying process can ensure microbiological safety in food production if the air circulating in the equipment has adequate hygienic properties. The microwave irradiation technology can be used successfully to inhibit microbes in foods, in this case fruits. However, the same treatment parameters cannot be applied to different fruits

Application of the SPME technique for determinate the quality indicators of dairy products

Solid Phase Microextraction (SPME) is a relatively new extraction technique that combines taking samples from a mixture with a simpler desorption of the components to be analyzed of the unenriched sample in its original state in the analytical instrument. Based on a large number of publications in the literature, the authors describe the possibilities of using the SPME technique in the case of dairy products. The main groups of components that can be detected by the SPME sampling procedure, such as fatty acids, aldehydes and ketones, esters, alcohols, sulfur-containing organic compounds, furans, phenols and terpenoids are presented, through examples in the literature. Due to the limited scope of the manuscript, the authors report only on the possibilities of sample preparation using the SPME technique. Instrumental analytical methods following solid state microextraction, mainly using gas or liquid chromatography, are not described. Details of instrumental analyses are available in the cited literature sources

Gyümölcsjoghurtok eltarthatóságának vizsgálata az ízesítőanyagok kezeléseinek függvényében

A tej és a tejtermékek az emberiség táplálkozásának egyik alapját képezik értékes összetevőik és kellemes érzékszervi tulajdonságaik miatt. Kutatásaink célja volt azt vizsgálni, hogy a különböző hőkezelési eljárások (mikrohullámú sugárzás, aszalás), hogyan befolyásolják a tejtermékek (joghurt) eltarthatóságát mikrobiológiai vonatkozásban. Méréseink során a termékek előállításánál felhasznált ízesítőanyagok (alma, banán) eltérő hőkezelési paramétereinek hatását vizsgáltuk a termékek mikrobiológiai tulajdonságaira és ezáltal annak eltarthatóságára nézve. Kísérleteink során az adalékanyagok kezelési formáiként a hagyományos aszalásos (55 °C, 24 óra) és a mikrohullámú sugárzásos technológiát (800 W, 55 °C, 10 perc) alkalmaztunk. Összehasonlításokat végeztünk mikrobiológiai paraméterek tekintetében (összcsíraszám, élesztő/penész-szám és E. coli/coliform-szám). Eredményeink alapján úgy véljük, hogy az aszalásos eljárás abban az esetben biztosíthat mikrobiológiai biztonságot élelmiszer előállítása során, ha a berendezésben keringő levegő megfelelő higiéniai tulajdonságokkal bír. A mikrohullámú sugárzási technológia az élelmiszerek – jelen esetben gyümölcsök - esetében sikeresen alkalmazható mikrobák gátlására. Ugyanaz a kezelési paraméter azonban nem alkalmazható különböző gyümölcsök esetén

Impact assessment of microwave treatment of raw cow's milk on its microbiological properties

The aim of our research was to examine the impact of microwave radiation on the microbiological parameters of raw cow’s milk. In the measurements, our samples (raw cow’s milk) were treated at different power levels [100, 200, 300, 400, 496 (~500), and 600 W], and the effects of microwave irradiation were assessed regarding total plate count and yeast cell count. Treatment temperature was maximized in all cases (40 °C) in order to eliminate the thermal effect generated by microwaves, and hence, to justify the possible microbial inhibitor or destruction impact of the non-thermal effect of radiation. Based on the results, microwave treatment had an impact on both the total plate count and the yeast cell count as well. Treatments were performed to justify the non-thermal effect of the treatments, and significant results were obtained (p≤0.05)

The effect of the supply chain exerting physical stress on the microbiological status of bottled natural mineral water

Mineral water consumption increased dramatically in the last 30 years. One reason for this change lies in the changing consumer behaviour: consumers are increasingly recognizing the importance of healthy nutrition and appreciate the beneficial nutritional physiological properties of mineral water. Local mineral water harmonizes well with imported waters. Bottled mineral water may travel several hundred kilometres until it reaches consumers. In the present study, the dynamic mechanical vibration caused by transporting on public roads was simulated in laboratory vibration tests then samples were subjected to microbiological examinations in compliance with legislations currently in force. Due to this vibration, the initial microbe count increased by two orders of magnitude, while after terminating the 4-hour mechanical action it decreased gradually. Growing dynamics of microbes constituting the total germ count at 22 °C and 37 °C were almost similar

Impact assessment of microwave treatment of raw cow's milk on its microbiological properties

The aim of our research was to examine the impact of microwave radiation on the microbiological parameters of raw cow’s milk. In the measurements, our samples (raw cow’s milk) were treated at different power levels [100, 200, 300, 400, 496 (~500), and 600 W], and the effects of microwave irradiation were assessed regarding total plate count and yeast cell count. Treatment temperature was maximized in all cases (40 °C) in order to eliminate the thermal effect generated by microwaves, and hence, to justify the possible microbial inhibitor or destruction impact of the non-thermal effect of radiation. Based on the results, microwave treatment had an impact on both the total plate count and the yeast cell count as well. Treatments were performed to justify the non-thermal effect of the treatments, and significant results were obtained (p≤0.05)

SPME technika alkalmazása a tejipari termékek minőségi mutatóinak meghatározásához

A szilárdfázisú mikroextrakció (Solid Phase Micro Extraction – SPME) egy viszonylag újkeletű extrakciós technika, amely egyesíti a keverékből vett minta kinyerését, valamint a dúsítás nélküli, eredeti állapotban lévő minta vizsgálandó komponenseinek egyszerűbb deszorpcióját az analitikai berendezésben. A szerzők a szakirodalomban jelen lévő nagyszámú közlemény alapján ismertetik a (SPME) technika felhasználhatóságának lehetőségeit tejipari termékek esetében. Bemutatja a SPME mintavételi eljárás segítségével detektálható főbb vegyületcsoportokat, szakirodalmi példákon keresztül, úgy, mint zsírsavak, aldehidek és ketonok, észterek, alkoholok, kéntartalmú szerves vegyületek, furánok, fenolok és terpenoidok. A szerzők a kézirat korlátozott terjedelme miatt csak az SPME technikával végzett mintaelőkészítés lehetőségeiről számolnak be. A szilárdfázisú mikroextrakciót követő – elsősorban gáz- és folyadékkromatográfiás – műszeres analitikai vizsgálati módszereket nem ismertetik. A műszeres elemzések részletei a hivatkozott irodalmi forrásokban rendelkezésre állnak

Purification of Model Dairy Wastewaters by Ozone, Fenton Pre-treatment and Membrane Filtration

This study aimed to investigate the effect of ozone and Fenton-reaction as a pre-treatment before ultrafiltration of model dairy waste waters containing sodium caseinate. Filtration resistances and pollutant retentions were determined and compared. It was found, that both pre-treatment increased the retention, achieving almost 100 % pollutant elimination efficiency after short term pre-oxidation. The effect of Fe-ion concentration on Fenton pretreatment efficiency also was examined, and it was found that higher concentration resulted in decreased filtration resistances, revealing that coagulation-flocculation effect of reactants has dominant role in the protein separation efficiency. The presence of lactose also affects the pollutant removal efficiency, it promotes fouling in presence of Fenton reagents

Investigation of the shelf life of fruit yogurts as a function of the treatment of flavoring substances

Milk and dairy products represent one of the foundations of the human diet because of their valuable ingredients and pleasant sensory properties. The aim of our research was to investigate how different heat treatment processes (microwave irradiation, drying) affect the shelf life of dairy products (yogurt) from a microbiological point of view. In the course of our measurements, the effects of the different heat treatment parameters of the flavoring substances used in the production of the products (apples, bananas) on the microbiological properties of the products and, thus, on their shelf life were investigated. In our experiments, conventional drying (55 °C, 24 hours) and microwave irradiation technology (800 W, 55 °C, 10 min) were used as treatment forms of the additives. Comparisons were made in terms of microbiological parameters (total viable count, yeast/mold count and E. coli/coliform count). Based on our results, we believe that the drying process can ensure microbiological safety in food production if the air circulating in the equipment has adequate hygienic properties. The microwave irradiation technology can be used successfully to inhibit microbes in foods, in this case fruits. However, the same treatment parameters cannot be applied to different fruits