Browse

You are looking at 81 - 90 of 8,214 items for :

  • Biology and Life Sciences x
  • Refine by Access: All Content x
Clear All
Acta Alimentaria
Authors:
X. Bai
,
H.F. Gao
,
X. Li
,
Y.L. Li
,
M.Z. Lan
,
L. Li
,
Z.D. Zhao
,
Z.B. Li
, and
J. Wang

Abstract

As research advances, it is generally acknowledged that non-Saccharomyces yeast contribute to the addition of aromatic compounds during mead fermentation. In this experiment, eight different non-Saccharomyces strains and Saccharomyces cerevisiae co-fermentation, their aroma composition, and basic physicochemical parameters were investigated. More than 30 compounds with favourable impact were discovered using solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Co-fermentation of non-Saccharomyces spp. and S. cerevisiae can affect the concentration of volatile compounds, so that the mead presents different aroma characteristics. Co-fermented meads of Wickerhamomyces anomalus strains and S. cerevisiae (Wa 27-Sc and Wa 5-Sc) had higher alcohol, acids, aldehyde, and ester concentrations than those fermented with S. cerevisiae alone. In terms of taste, Wa 27-Sc was superior to Wa 5-Sc. Overall, the Wa 27-Sc received the highest score for its strong secondary aroma and good mouthfeel. The results show that the W. anomalus Wa 27 strain has a good potential to produce high quality mead.

Restricted access

Abstract

The study investigates the antimicrobial effects of the Hypericum crenulatum ethanolic (HCE) extract against 14 different food pathogens and their biofilm-forming abilities in response to HCE treatment. The phenolic acid composition of the HCE extract was also determined using an HPLC-DAD detector. The antimicrobial activity of HCE extract was assessed using the disc diffusion and microdilution methods. According to the findings, the methicillin-resistant Staphylococcus aureus ATCC 43300, Listeria monocytogenes RSKK 472, and Listeria innocua ATCC 33090 strains exhibited the lowest minimum inhibitory concentration (MIC) values at a concentration of 2 μg mL−1. Based on the disc diffusion test results, the largest zone of inhibition of HCE extract against foodborne pathogens was seen against Bacillus cereus, and the diameter of the inhibition zone increased with the concentration of HCE extract (P < 0.05). In terms of phenolic acid composition of HCE extract, the phenolic acids with the highest and lowest amounts were caffeic acid (59.92 mg g−1) and p-coumaric acid (13.61 μg g−1), respectively. Our study determined that the HCE extract demonstrated antimicrobial, bactericidal, and antibiofilm activities against some foodborne pathogens. These effects reveal its potential for improving food safety by inhibiting the growth of these pathogens.

Restricted access

„Két lábbal a földön, avagy miként próbál a talajtan válaszokat adni a globális kihívásokra”

Beszámoló a HUN-REN ATK Talajtani Intézetének Magyar Tudomány Ünnepe előadónapjáról

Agrokémia és Talajtan
Author:
Kitti Balog
Restricted access
Progress in Agricultural Engineering Sciences
Authors:
Donald Bimpong
,
Lois Amponsah Adofowaa
,
Ama Agyeman
,
Abena Boakye
,
Ibok Nsa Oduro
,
Ellis William Otoo
, and
John-Lewis Zinia Zaukuu

Abstract

Peanut butter and yoghurt are targeted for adulteration intended at consumer deception. This study aimed to fingerprint and detect peanut butter and yoghurt adulteration with cassava flour and starch using Near Infrared Spectroscopy (NIRS) in a quasi-experimental approach. Ingredients for laboratory sample preparation were obtained from the Kumasi Metropolis. Peanut butter was adulterated at 1, 3, 5, 10, 15, 20% w/w and yoghurt at 0.25, 0.5, 1, 3, 5, 10, 15, 20, 25, 45, 50% w/w. Selected concentrations mimicked practices on the market. Marketed products were randomly sampled from six markets in the Kumasi Metropolis to validate the study models. Samples were scanned with a hand-held NIRS in triplicates. Chemometric (Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and Partial Least Square Regression (PLSR) models) statistical methods were employed to develop classification and prediction models. Peaks with spectral bands such as 1050 , 1200 and 1450 nm were observed for peanut butter and 990–1100 nm, 1100–1200 nm and 1300–1408 nm were observed for yoghurt in the NIR spectrum. Some yoghurt brands were suspected of containing cassava starch, while Peanut butter from the different markets differed based on classification models. Cassava flour and starch concentrations were quantitatively predicted by PLSR with an R2 CV of 0.98 and an error of 0.9 g/100 g (low error).

Restricted access
European Journal of Microbiology and Immunology
Authors:
Ellis Kobina Paintsil
,
Wycliffe O. Masanta
,
Annika Dreyer
,
Leonid Ushanov
,
Stella I. Smith
,
Hagen Frickmann
, and
Andreas E. Zautner

Abstract

Campylobacter infections and campylobacteriosis-associated post-infectious sequelae are a significant global health burden that needs to be addressed from a specific African perspective. We conducted a comprehensive literature search on NCBI PubMed to compile a comprehensive narrative review article on Campylobacter infections in Africa, focusing on key aspects in human and veterinary medicine as well as food hygiene. We specifically focused on the epidemiology of enteropathogenic Campylobacter spp. in sub-Saharan and North Africa considering antimicrobial susceptibility. The most significant sequela resulting from molecular mimicry to Campylobacter surface structures is the Guillain-Barré syndrome, which was mainly examined in the context of limited studies conducted in African populations. A dedicated subsection is allocated to the limited research on the veterinary medically important species Campylobacter fetus. There are significant differences in the composition of the gut microbiome, especially in rural areas, which affect the colonization with Campylobacter spp. and the manifestation of campylobacteriosis. There may be a problem of overdiagnosis due to asymptomatic colonization, particularly in the detection of Campylobacter using molecular biological techniques. To reduce the colonization and infection rate of Campylobacter, we propose implementing several control measures and urge further research to improve the current understanding of the peculiarities of campylobacteriosis in Africa.

Open access

A talaj katabolikus aktivitás mintázatának elemzése mikrorespirációs (MicroResp) módszerrel

Analysis of soil catabolic activity patterns by micro-respiration (MicroResp)

Agrokémia és Talajtan
Authors:
Tibor Szili-Kovács
,
Márton Mucsi
,
Anna Füzy
,
Tünde Takács
, and
Andrea K. Borsodi

A talaj mikrobiális közösségének funkcionális diverzitása a talaj ökoszisztéma szolgáltatások jelentős részéhez hozzájárul, sok esetben meghatározó jelentőségű. Többféle kísérleti és elméleti megközelítés közül a katabolikus aktivitás-mintázat mikrorespirációs – MicroResp™ – módszerrel történő megközelítését mutatjuk be. A módszer a régebbről ismert szubsztrát-indukált respiráció több-szubsztrátos, mikrotiter lemez alapú kiterjesztése, amivel a talaj mikroba-közösség in-situ közösségi-szintű fiziológiai mintázata határozható meg. Mivel az egyes mikroorganizmusok szubsztrát-hasznosítása eltérő, a mikroba-közösség aktuális összetételétől, abundanciájától függően változó a szubsztrát hasznosítási mintázat egy-egy talajminta esetében. Az alkalmazott szubsztrátok köre tetszőleges, rendszerint egyszerű cukrok, aminosavak, aminok, karbonsavak. A módszer gyors, érzékeny, megbízható, ezért alkalmazása tervezett kísérletekben és talajmonitoring programokban egyaránt javasolható.

Open access

Abstract

Medication-related osteonecrosis of the jaw (MRONJ) is an increasingly common consequence of antiresorptive treatment, which often leads to the development of necrotic exposed bone surfaces with inflammatory processes affecting the jawbone. Although the development of MRONJ is often associated with the inflammatory response or infections caused by the colonizing members of the oral microbiota, the exact pathogenesis of MRONJ is still not fully understood. In the present paper, we aimed to provide additional, microbiological culture-supported evidence, supporting the “infection hypothesis” that Actinomyces spp. and related organisms may play an important pathogenic role in the development of MRONJ and the resulting bone necrosis. In our case series, all patients presented with similar underlying conditions and anamnestic data, and have received antiresorptive medications (bisphosphonates or a RANK ligand (RANKL) inhibitor) to prevent the occurrence or progression of bone metastases, secondary to prostate cancer. Nevertheless, a few years into antiresorptive drug therapy, varying stages of MRONJ was identified in the mentioned patients. In all three cases, quantitative microbiological culture of the necrotic bone samples yielded a complex microbiota, dominated by Actinomyces and Schaalia spp. with high colony counts. Additionally, our followed-up case series document the treatment of these patients with a combination of surgical intervention and long-term antibiotic therapy, where favourable clinical responses were seen is all cases. If the “infection hypothesis” is valid, it may have significant consequences in the preventative and therapeutic strategies associated with this disease.

Open access

Abstract

The soaking step of dry pulse products' – e.g. chickpeas' – food processing is a time consuming process. Soaking time can be significantly reduced by ultrasonic treatment or using higher processing temperatures. The effect of ultrasonic treatment can be investigated by examining the soaking water characteristics. Ultrasound-assisted soaking of chickpeas was performed at 25, 35 and 45 °C, respectively. Additionally, control samples were also prepared without ultrasonic treatment at the same temperatures. The dynamics of the fitted curve clearly shows the relationship namely the higher the treatment temperature, the faster the hydration of the raw material for both untreated and treated groups. In contrast to control group, swelling rate of 2.00 – except the group 45 °C – is not achieved during ultrasound-assisted soaking. In case of treated group, the swelling rate was about 1.90 for all temperatures applied. The ANOVA test shows that the color of the ultrasonically treated samples was significantly different compared to the control (F (5;12) = 207.86; P < 0.001). Average dry matter content and °Brix value were significantly higher in the ultrasound treated group compared to the control in case of all temperatures. This may indicate the destructive effect of ultrasound, which may cause more components to dissolve out of the raw material by the end of the soaking process.

Open access

Abstract

The objective of our work was to analyze the differences between four nut pastes, which were the following: walnut, peanut, pistachio, and tahini (sesame). The process technology of them is unknown, however, all the products contain 100% nut without any additives or flavoring.

The paste samples were measured at 25 ± 0.2 °C. The apparent viscosity at a 10 1/s shear rate during flow curve recording, and the dynamic viscosity at a constant 20 1/s shear rate was determined by viscosity measurement with the use of the MCR302 modular compact rheometer. The L*a*b* color components were determined by ColorLite sph850 spectrometer, finally, the particle sizes and shapes of the samples were analyzed by the high-speed image analysis instrument QICPIC.

The apparent viscosity and the average dynamic viscosity values of the four nut pastes were significantly different from each other. Differences were found between each paste according to the L*a*b* parameters. The complex structures of the particles are detailed and measurable, whereby the lengths and diameters of the particles can reliably be determined and fine deviations between the samples are detected. The sphericity decreases slightly with increasing particle size which means that bigger particles are more irregularly shaped.

Open access

Abstract

With growing attention to health and lifestyle changes, functional foods have become crucial and in demand. These foods are a rich source of probiotics and prebiotics, but most probiotic products are dairy-based, making them inappropriate for people with lactose intolerance or milk protein allergies. Nevertheless, egg white offers a viable substitute and is considered one of the best sources of functional proteins. As an alternative food matrix, they come highly recommended for those who are hypersensitive to dairy products or who follow a high-protein diet, such as athletes. In this context, egg-white drink with different carbohydrate sources, including monosaccharide (fructose) and oligosaccharide (fructooligosaccharide), was fermented by Lacticaseibacillus casei 01. After 24 h of fermentation, the total cell count was higher than 8 log10 CFU mL−1 thus, the egg white drink was suitable for L. casei 01 to grow. Additionally, the survival of L.casei 01, the pH value, and the rheological properties of fermented beverages within three weeks of refrigerated storage were also investigated. Throughout the storage period, the control samples exhibited considerably lower cell count and higher pH values compared to the samples with carbohydrate sources, also, samples containing the same carbohydrate source showed no noticeable changes. Viscosity measurements of the studied samples showed a shear thickening behaviour during the time.

Open access