Acceleration of proteolysis, flavour development and enhanced bioactivity in a model cheese using Kuflu cheese slurry: An optimisation study

Incorporation of ultrasound-assisted treatment in cheese to accelerate ripening of Kaşar cheese: Changes in cheese microbiota, proteolysis, enzyme activities and volatile profiles

This study aimed to assess the impact of using LAB strains (Lactobacillus helveticus DPC 4571 and Lactobacillus casei ATCC 334) directly or after sonication on the quality and ripening of Kaşar cheese. Experimental cheeses were produced with a combination of cheese starters (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus), adjuncts and sonicated cultures. The cheeses showed remarkable variations in titratable acidity and pH. The bacterial counts showed that sonication was effective on adjunct cultures, causing faster and stronger autolysis of L. helveticus DPC 4571 and an increase in L. casei ATCC 334 during ripening. Cheeses containing adjunct cultures exhibited higher proteolysis, with increased hydrolysis of αs1- and β-caseins. Aminopeptidases activities increased during ripening by adjuncts and sonicated-adjunct cultures. The use of adjunct culture resulted in a greater increase in the free amino acid content. Adjuncts and sonicated-adjunct cultures increased both the quantity and diversity of some volatiles. In conclusion, the inclusion of sonicated culture in the starter system offered a potential approach to accelerate cheese ripening and improve cheese quality.

Improvement of compositional, textural, and rheological characteristics in plant-based cheese analogs fermented by kefir grain

Although plant-based cheese has been developed as a healthful food, it has limitations in terms of texture and flavor. In this study, novel soybean-based cheese analogs were prepared using soy protein isolate and kefir grains for improved properties. The analogs containing 3 % (w/v) soy protein isolate exhibited high water-holding capacity (90.80 %), and the sample prepared with 0.3 % (w/v) CaCl2 showed the high hardness (0.52 N). Additionally, hydrophobic interactions mainly contributed to structure formation and a significant proportion (> 90 %) of immobilized water was determined using low-field nuclear magnetic resonance analysis. Furthermore, the enhanced thermal stability and secondary structures of the analogs were demonstrated using thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray diffraction. The porous and compact microstructures of the analogs were observed using scanning electron microscopy. Our results provide an innovative approach for the preparation and application of plant-based cheese analogs using kefir grains.

Comparison of hyperspectral imaging and spectrometers for prediction of cheeses composition

Artisanal cheeses are part of the heritage and identity of different countries or regions. In this work, we investigated the spectral variability of a wide range of traditional Brazilian cheeses and compared the performance of different spectrometers to discriminate cheese types and predict compositional parameters. Spectra in the visible (vis) and near infrared (NIR) region were collected, using imaging (vis/NIR-HSI and NIR-HSI) and conventional (NIRS) spectrometers, and it was determined the chemical composition of seven types of cheeses produced in Brazil. Principal component analysis (PCA) showed that spectral variability in the vis/NIR spectrum is related to differences in color (yellowness index) and fat content, while in NIR there is a greater influence of productive steps and fat content. Partial least squares discriminant analysis (PLSDA) models based on spectral information showed greater accuracy than the model based on chemical composition to discriminate types of traditional Brazilian cheeses. Partial least squares (PLS) regression models based on vis/NIR-HSI, NIRS, NIR-HSI data and HSI spectroscopic data fusion (vis/NIR + NIR) demonstrated excellent performance to predict moisture content (RPD > 2.5), good ability to predict fat content (2.0 < RPD < 2.5) and can be used to discriminate between high and low protein values (∼1.5 < RPD < 2.0). The results obtained for imaging and conventional equipment are comparable and sufficiently accurate, so that both can be adapted to predict the chemical composition of the Brazilian traditional cheeses used in this study according to the needs of the industry.

Determination of the effects of proteolysis-based changes by adjunct lactobacilli on the bioactivity (ACE-inhibitory and antioxidant activities) of cheese: a model cheese study

Bioactive properties, proteolysis and microbiology of model cheeses with and without adjunct lactobacilli (Lactobacillus helveticus, Lactiplantibacillus plantarum, Lactobacillus bulgaricus and L. casei) were studied during 120 days of storage at 8 or 16 °C. Bioactive properties were observed in peptide fractions (< 3 kDa, 3-10 kDa, < 10 kDa) separated using ultrafiltration membranes. Antioxidant activity of these fractions was determined by radical scavenging assays as ABTS [2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)]. Angiotensin-converting enzyme-inhibitory (ACE-i) activity (% and IC50) and peptide profiles of 70% ethanol-soluble and -insoluble fractions were determined by RP-HPLC. Use of lactobacilli as an adjunct culture significantly changed the RP-HPLC peptide profiles of the cheeses; however, slight changes were observed in the patterns of urea-polyacrylamide gel electrophoresis. Fractions smaller than 3 kDa had higher ACE-i and antioxidant activities for all cheese samples. In conclusion, this study indicates that the addition of lactobacilli as an adjunct culture contributed to the formation of bioactive compounds in the model cheeses and also changed the proteolysis levels.