Effect of inulin on the growth and survival of Bifidobacterium longum BB536 in fermented goat’s and cow’s milk

Fermentirani mliječni napitci proizvedeni su od standardiziranoga kozjega i kravljeg mlijeka (2,9 % mliječne masti) uz dodatak 3 % obranog mlijeka u prahu (kontrolni uzorci), ili uz dodatak 2 % inulina i 1 % obranog mlijeka u prahu (eksperimentalni uzorci). Fermentacija uzoraka provedena je pri 40 °C uporabom termofilne jogurtne kulture YC-380 i probiotičke kulture Bifidobacterium longum BB536. Kod svih je uzoraka poželjna kiselost (pH oko 4,5) postignuta za oko 5,5 h. Broj živih stanica probiotičke kulture (logN/mL) porastao je tijekom fermentacije podjednako za sve uzorke (oko 1,4 logaritamske jedinice), osim za uzorak kravljeg mlijeka obogaćenog inulinom u kojem je porast bifidobakterija bio najveći (oko 1,7 logaritamske jedinice). Tijekom trajanja fermentacije nešto brži pad pH-vrijednosti uočen je kod uzoraka od kozjeg mlijeka u odnosu na kravlje. Na kraju fermentacije između ispitivanih uzoraka nije bilo statistički značajne razlike u pH-vrijednostima (P>0,05), bez obzira na vrstu mlijeka ili dodatak inulina. Tijekom 30 dana čuvanja fermentiranih napitaka pri temperaturi hladionika (oko 6 °C) nešto niže pH-vrijednosti zabilježene su kod uzoraka kravljeg mlijeka u odnosu na kozje, osobito kod kravljeg mlijeka obogaćenog inulinom. Do petnaestog dana čuvanja u svim uzorcima uočen je porast broja živih stanica probiotičkih bakterija, dok je od 20. do 30. dana zabilježen njihov pad za oko 0,5 logaritamske jedinice. U kozjem mlijeku bilo je nešto slabije preživljavanje bifidobakterija nego u kravljem. Broj bifidobakterija u uzorcima obogaćenim inulinom zadnji dan čuvanja u odnosu na kontrolne uzorke bio je veći za oko 0,3 logaritamske jedinice, bez obzira na vrstu mlijeka. U svim uzorcima nakon 30 dana čuvanja u hladioniku osigurana je preporučena koncentracija bifidobakterija na osnovi koje se istraživani fermentirani napitci ubrajaju u probiotičke.Fermented dairy products were made from standardized goat and cow milk (2.9 % milk fat) with addition of 3 % skimmed milk powder (control samples), or with addition of 2 % inulin and 1 % skimmed milk powder (experimental samples). Fermentation of samples was carried out at 40 °C by thermophilic yoghurt culture YC-380 and probiotic culture Bifidobacterium longum BB536. Desired acidity (pH around 4.5) was achieved in all samples in about 5.5 h. Viable count of probiotic strain (logN/m) increased for all samples for on average 1.4 logarithmic units except for the sample of cow’s milk supplemented with inulin, which exhibited the highest growth of bifidobacteria for approximately 1.7 logarithmic units. During fermentation somewhat faster decrease of pH-value was observed in goat milk samples compared to cow milk samples. At the end of fermentation there was no statistically significant difference (P>0.05) in pH-values regardless of milk origin or inulin addition. During thirty days of fermented drink storage at lower temperature (about 6 °C), slightly lower pH-values were observed in cow milk samples compared to goat milk, especially in cow milk enriched with inulin. During storage, until the 15th day, an increase in the number of viable count of probiotic bacteria was observed in all samples, while from 20th to 30th day a decrease of 0.5 logarithmic units of the same parameter was recorded. In goat milk their survival was somewhat smaller compared to cow milk. The number of bifidobacteria in samples supplemented with inulin on the last day of storage, compared to control samples, was higher for 0.3 logarithmic units, regardless of the milk origin. After thirty days of refrigerated storage, recommended concentration of bifidobacteria was insured in all samples, thus directly implying that these fermented drinks can be included in probiotics

Rheological properties of ultrasound treated apple, cranberry and blueberry juice and nectar

Ultrasound is non-thermal food processing technique that has been used in food processing very extensively for the last 10 years. The objective of this study was to investigate the effect of high power ultrasound and pasteurization on rheological properties (n and k) of apple, cranberry and blueberry juice and nectar. Samples were treated according the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time, temperature of sample and amplitude). Thermosonication and sonicaton of juice and nectar samples have been performed. It was found that all samples of untreated, pasteurized and ultrasonically treated apple, cranberry and blueberry juices and nectars shows non-Newtonian dilatant fluid characteristics (n > 1). The interaction of treatment time and temperature of sample (BC) and temperature (C) of sample of apple juice had statistically significant effect on flow behavior index (n) for ultrasound treated apple juice. Interaction of treatment time and temperature of sample (BC) has statistically significant effect on the flow behavior index (n) for blueberry nectar. Also, there is statistically significant effect of temperature (C) of sample on consistency coefficient (k) for ultrasound treated apple juice

Influence of refrigeration and ageing time on textural characteristics of fresh meat

Research of the textural characteristics of pork, beef and baby beef meat samples was conducted. Hardness and adhesivity of the meat was measured immediately after slaughtering, then after 24, 48 and 72 hours. Half of the samples were kept at room temperature, while the other half were refrigerated at 4 C. The results showed that the hardness and adhesivity suddenly dropped during the first 24 hours (up to 345 N, or 41.7 %). After next 48 hours of storage, the values of measured textural properties showed a slight decrease (only additional 15.6 %). The refrigerated samples retained their textural properties a lot better (31 % decrease in hardness during first 24 h, additional 7.4 % in the next 48 hours) than the non-refrigerated ones. In correlation with consumer and industry experience with the texture of cooked or fried meat, refrigeration is a better choice after 48 hours, while after that period, meat at room temperature, is too soft for further processing

Influence of Frying Time and Addition of Rice Starch on Oil Uptake and Textural Properties of Fried Coated Chicken Meat

Rice starch in shares of 6, 8 and 10 % was used as replacement for eggs in the coating mixtures used for coating of meat before frying. After frying of meat at 170 0C for 4, 6 and 8 minutes, effects of frying time and addition of starch on oil uptake and meat texture were evaluated. Instrumental texture analysis of fried coated chicken meat was conducted, as well as Soxhlet method for determining of oil content in samples. Statistical analysis of relevant texture properties of fried meat was performed. Hardness of fried meat samples decreased with increase of the starch content in mixture. Elasticity of meat increased as a result of coatings water holding capability and consequent prevention of meat drying. Oil content in samples coated with mixtures containing rice starch decreased with increase of starch share. Optimal frying time was 6 minutes, which with 10 % of mass share of rice starch produced samples with 35.54 % less oil

Determination of Textural Properties of Gouda Cheese

Tekstura kao manifestacija nekih reoloških svojstava namirnice jedna je od osnovnih organoleptičkih svojstava, te ima vrlo važnu ulogu pri rukovanju, obradi i ponašanju namirnica. Potrošačima je također tekstura jedan od važnijih parametara kojim se rukovode prilikom odabira proizvoda. Na analizatoru teksture TA.HDPlus izvršena je instrumentalna analiza pet sireva Gouda različitih proizvođača koji su prisutni na hrvatskom tržištu. Od teksturalnih parametara ispitivane su tvrdoća, rad potreban za žvakanje, elastičnost i adhezivnost te njihova ovisnost o udjelu suhe tvari.Najtvrđim (11,88 N ± 1,79) su se pokazali uzorci s najvećim udjelom suhe tvari (55 %). Padom udjela suhe tvari smanjuju se vrijednosti tvrdoće, adhezivnosti i rada potrebnog za prvi zagriz. Elastičnost raste s porastom udjela vode te je najveća elastičnost bila 14,02 mm, uz 50 % udjela vode. Rad potreban za prvi zagriz linearno ovisi o sva tri teksturna parametra gdje je 138,24 mJ najveća dobivena vrijednost pri 55 % suhe tvari.Texture as a manifestation of some rheological properties of foodstuffs is one of the primary organoleptic properties. It has important role in handling, processing and behaviour of the foodstuffs. From consumer aspect, texture is also one of the more important parameters which they use for their buying decisions. Instrumental analysis on TA.HDPlus texture analyzer of five Gouda cheeses from various Croatian producers was conducted. From wide range of textural properties, hardness, work for mastication, elasticity and adhesivity were chosen for testing, as well as for comparing with dry matter content. Hardest (11,88 N ± 1,79) samples have largest share of dry matter (55 %). With decrease of dry matter content, values for hardness, adhesivity and work dropped. Elasticity rise with increase of water content, i.e. largest elasticity was 14,02 mm, with 50 % water content. Work linearly depends on all three measured textural properties. 138,24 mJ was largest measured value for sample, which contain 55 % of dry matter

Aroma profile and sensory properties of ultrasound-treated apple juice and nectar

Ultrasonication is a nonthermal food processing method that is used in several applications (extraction, treatment before drying, freezing, inactivation of microorganisms, etc.) in ultrasound processing. The objective of this study is to investigate the effect of high power ultrasound and pasteurisation on the aroma profile and sensory properties of apple juice and nectar. Samples were treated according to the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time: 3, 6 and 9 min, sample temperature: 20, 40 and 60 °C, and amplitude: 60, 90 and 120 μm). The aromatic profiles of juices showed that, compared to the untreated samples of juices and nectars, ultrasonic treatment led to the formation of new compounds (which were not present in the untreated samples) or to the disappearance of compounds that were found in the untreated samples. Samples treated at the highest amplitude (120 μm) were used for evaluation and comparison with untreated and pasteurised samples using electronic tongue study. Principal component analysis confirmed the results of electronic tongue study, which showed that the ultrasound-treated and pasteurised juices had different scores compared to the untreated samples

Aromatski profil i senzorska svojstva jabučnog soka i nektara tretiranih ultrazvukom

Ultrasonication is a nonthermal food processing method that is used in several applications (extraction, treatment before drying, freezing, inactivation of microorganisms, etc.) in ultrasound processing. The objective of this study is to investigate the effect of high power ultrasound and pasteurisation on the aroma profile and sensory properties of apple juice and nectar. Samples were treated according to the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time: 3, 6 and 9 min, sample temperature: 20, 40 and 60 °C, and amplitude: 60, 90 and 120 μm). The aromatic profiles of juices showed that, compared to the untreated samples of juices and nectars, ultrasonic treatment led to the formation of new compounds (which were not present in the untreated samples) or to the disappearance of compounds that were found in the untreated samples. Samples treated at the highest amplitude (120 μm) were used for evaluation and comparison with untreated and pasteurised samples using electronic tongue study. Principal component analysis confirmed the results of electronic tongue study, which showed that the ultrasound-treated and pasteurised juices had different scores compared to the untreated samples.Ultrazvuk se može primijeniti kao netermička metoda za ekstrakciju sastojaka, obradu hrane prije sušenja, zamrzavanje, inaktivaciju mikroorganizama i sl. Svrha je ovoga rada bila istražiti utjecaj ultrazvuka velike snage, te postupka pasterizacije na aromatski profil i senzorska svojstva jabučnog soka i nektara. Uzorci su obrađeni ultrazvukom velike snage i niske frekvencije od 20 kHz pri različitim uvjetima (vrijeme tretmana: 3, 6 i 9 min; temperatura: 20, 40 i 60 °C i amplituda: 60, 90 i 120 μm). Iz aromatskog se profila jabučnog soka i nektara može zaključiti da je nakon obrade ultrazvukom došlo do nastanka novih spojeva, a istodobno i do razgradnje nekih spojeva koji su pronađeni u netretiranim uzorcima. Uzorci izloženi ultrazvučnim valovima najveće amplitude (120 μm) uspoređeni su s netretiranim i pasteriziranim uzorcima pomoću elektroničkog jezika. Analizom osnovnih komponenata (engl. principal component analysis - PCA) utvrđeno je da uzorci obrađeni ultrazvukom i pasterizirani sokovi imaju drukčije vrijednosti od netretiranih sokova, što je potvrđeno i senzorskom analizom

Aromatski profil i senzorska svojstva jabučnog soka i nektara tretiranih ultrazvukom

Ultrasonication is a nonthermal food processing method that is used in several applications (extraction, treatment before drying, freezing, inactivation of microorganisms, etc.) in ultrasound processing. The objective of this study is to investigate the effect of high power ultrasound and pasteurisation on the aroma profile and sensory properties of apple juice and nectar. Samples were treated according to the experimental design, with high power sonicator at ultrasound frequency of 20 kHz under various conditions (treatment time: 3, 6 and 9 min, sample temperature: 20, 40 and 60 °C, and amplitude: 60, 90 and 120 μm). The aromatic profiles of juices showed that, compared to the untreated samples of juices and nectars, ultrasonic treatment led to the formation of new compounds (which were not present in the untreated samples) or to the disappearance of compounds that were found in the untreated samples. Samples treated at the highest amplitude (120 μm) were used for evaluation and comparison with untreated and pasteurised samples using electronic tongue study. Principal component analysis confirmed the results of electronic tongue study, which showed that the ultrasound-treated and pasteurised juices had different scores compared to the untreated samples.Ultrazvuk se može primijeniti kao netermička metoda za ekstrakciju sastojaka, obradu hrane prije sušenja, zamrzavanje, inaktivaciju mikroorganizama i sl. Svrha je ovoga rada bila istražiti utjecaj ultrazvuka velike snage, te postupka pasterizacije na aromatski profil i senzorska svojstva jabučnog soka i nektara. Uzorci su obrađeni ultrazvukom velike snage i niske frekvencije od 20 kHz pri različitim uvjetima (vrijeme tretmana: 3, 6 i 9 min; temperatura: 20, 40 i 60 °C i amplituda: 60, 90 i 120 μm). Iz aromatskog se profila jabučnog soka i nektara može zaključiti da je nakon obrade ultrazvukom došlo do nastanka novih spojeva, a istodobno i do razgradnje nekih spojeva koji su pronađeni u netretiranim uzorcima. Uzorci izloženi ultrazvučnim valovima najveće amplitude (120 μm) uspoređeni su s netretiranim i pasteriziranim uzorcima pomoću elektroničkog jezika. Analizom osnovnih komponenata (engl. principal component analysis - PCA) utvrđeno je da uzorci obrađeni ultrazvukom i pasterizirani sokovi imaju drukčije vrijednosti od netretiranih sokova, što je potvrđeno i senzorskom analizom