Characteristics of lactose-free frozen yogurt with κ-carrageenan and corn starch as stabilizers

Frozen yogurt is a type of dairy product that is considered to be a more healthful alternative to conventional ice cream due to its lower fat content and the presence of viable lactic acid bacteria. Lactose-free products are a growing trend in the dairy industry, and lactose-free yogurts and ice creams can both be found on the market. However, lactose-free frozen yogurt has not yet reached the market. In this study, we aimed to investigate the effect of adding κ-carrageenan (0.05, 0.1, and 0.15%) and corn starch (1, 2, and 3%) on acidity, texture, viscosity, overrun, melting properties, color attributes, and sensory characteristics of lactose-free frozen yogurts. Lactose was reduced by enzymatic hydrolysis during the fermentation process. The effectiveness of the hydrolysis was measured by HPLC, and lactose was reduced to 0.05% after 80 min of incubation with the enzyme. The addition of stabilizers did not change overrun and melting properties of frozen yogurt, but it did affect pH, titratable acidity, and color parameters. The product with 0.15% κ-carrageenan had the highest hardness and stickiness values. Moreover, κ-carrageenan had a positive effect on sensory attractiveness of lactose-free frozen yogurt, and it reduced the coarse texture in comparison with the control without stabilizers. A lactose-free frozen yogurt with good quality and nutritional characteristics was produced, particularly with the use of κ-carrageenan as stabilizer.     

Effect of dietary crude protein degradability and corn processing on lactation performance and milk protein composition and stability

The present study aimed to evaluate the effect of crude protein degradability and corn processing on lactation performance, milk protein composition, milk ethanol stability (MES), heat coagulation time (HCT) at 140°C, and the efficiency of N utilization for dairy cows. Twenty Holstein cows with an average of 162 ± 70 d in milk, 666 ± 7 kg of body weight, and 36 ± 7.8 kg/d of milk yield (MY) were distributed in a Latin square design with 5 contemporaneous balanced squares, 4 periods of 21 d, and 4 treatments (factorial arrangement 2 × 2). Treatment factor 1 was corn processing [ground (GC) or steam-flaked corn (SFC)] and factor 2 was crude protein (CP) degradability (high = 10.7% rumen-degradable protein and 5.1% rumen-undegradable protein; low = 9.5% rumen-degradable protein and 6.3% rumen-undegradable protein; dry matter basis). A significant interaction was observed between CP degradability and corn processing on dry matter intake (DMI). When cows were fed GC with low CP degradability, DMI increased by 1.24 kg/d compared with cows fed GC with high CP degradability; however, CP degradability did not change DMI when cows were fed SFC. Similar interactions were observed for MY, HCT, and lactose content. When cows were fed GC diets, high CP degradability reduced MY by 2.3 kg/d, as well as HCT and lactose content, compared with low CP degradability. However, no effect of CP degradability was observed on those variables when cows were fed SFC diets. The SFC diets increased dry matter and starch total-tract digestibility and reduced β-casein (CN) content (% total milk protein) compared with GC diets. Cows fed low-CP degradability diets had higher glycosylated κ-CN content (% total κ-CN) and MES, as well as milk protein content, 3.5% fat-corrected milk, and efficiency of N for milk production, than cows fed high-CP degradability diets. Therefore, GC and high-CP degradability diets reduced milk production and protein stability. Overall, low CP degradability increased the efficiency of dietary N utilization and MES, probably due to changes in casein micelle composition, as CP degradability or corn processing did not change the milk concentration of ionic calcium. The GC diets increased β-CN content, which could contribute to reducing HTC when cows were fed GC and high-CP degradability diets.     

Impact of Thermal Blanching and Thermosonication Treatments on Watercress (Nasturtium officinale) Quality: Thermosonication Process Optimisation and Microstructure Evaluation

The objectives of the present work were to optimise watercress heat and thermosonication blanching conditions, in order to obtain a product with better quality for further freezing, and to evaluate the effects of thermosonication on the microstructure of watercress leaves. In a chart of optimal time–temperature conditions for a 90% peroxidase inactivation (imposed constraint), vitamin C (objective function) and a-value (improvement toward green) were mathematically predicted for both heat and thermosonication blanching treatments. Two optimal thermosonication combinations were selected: 92 °C and 2 s, retaining 95% of vitamin C content and 5% a-value improvement, and a better condition in terms of practical feasibility, 86 °C and 30 s, allowing a 75% vitamin C retention and 8% a-value improvement. The experimental values, for each thermosonication optimal time–temperature zone, were in good agreement with the models' predicted responses. In terms of microstructure, thermosonicated watercress at 86 and 92 °C showed similar loss of turgor and release of chloroplasts. The proposed optimal thermosonication blanching conditions allow the improvement of the blanched watercress quality and consequently contribute for the development of a high-quality new frozen product. However, a suitable scale-up is mandatory for industrial implementation.     

Bioactive Phytochemicals from Wild Arbutus unedo L. Berries from Different Locations in Portugal: Quantification of Lipophilic Components

The lipophilic composition of wild Arbutus unedo L. berries, collected from six locations in Penacova (center of Portugal), as well as some general chemical parameters, namely total soluble solids, pH, titratable acidity, total phenolic content and antioxidant activity was studied in detail to better understand its potential as a source of bioactive compounds. The chemical composition of the lipophilic extracts, focused on the fatty acids, triterpenoids, sterols, long chain aliphatic alcohols and tocopherols, was investigated by gas chromatography–mass spectrometry (GC–MS) analysis of the dichloromethane extracts. The lipophilic extractives of the ripe A. unedo berries ranged from 0.72% to 1.66% (w/w of dry weight), and consisted mainly of triterpenoids, fatty acids and sterols. Minor amounts of long chain aliphatic alcohols and tocopherols were also identified. Forty-one compounds were identified and among these, ursolic acid, lupeol, α-amyrin, linoleic and α-linolenic acids, and β-sitosterol were highlighted as the major components. To the best of our knowledge the current research study provides the most detailed phytochemical repository for the lipophilic composition of A. unedo, and offers valuable information for future valuation and exploitation of these berries.     

Recent Advances in Lipase-Mediated Preparation of Pharmaceuticals and Their Intermediates

Biocatalysis offers an alternative approach to conventional chemical processes for the production of single-isomer chiral drugs. Lipases are one of the most used enzymes in the synthesis of enantiomerically pure intermediates. The use of this type of enzyme is mainly due to the characteristics of their regio-, chemo- and enantioselectivity in the resolution process of racemates, without the use of cofactors. Moreover, this class of enzymes has generally excellent stability in the presence of organic solvents, facilitating the solubility of the organic substrate to be modified. Further improvements and new applications have been achieved in the syntheses of biologically active compounds catalyzed by lipases. This review critically reports and discusses examples from recent literature (2007 to mid-2015), concerning the synthesis of enantiomerically pure active pharmaceutical ingredients (APIs) and their intermediates in which the key step involves the action of a lipase.     

Analysis of Damage on the Streptococcus mutans Immersed in Ozonated Water: Preliminary Study for Application as Mouth Rinse

Ozonated water has been demonstrated to induce significant results in terms of the elimination of microorganisms. The present study assessed the damage to Streptococcus mutans after exposure to ozonated water; the ozone generator was adjusted to provide an outlet concentration of 60 mg/L, the samples were submitted to different ozonation times 1, 2, 4, 6, and 10 mi. Scanning electron microscopy and atomic force images were obtained to identify damage to the bacteria, followed by reactive oxygen species (ROS) evaluation and microbial viability. The results showed a significant reduction in viability and the images evidenced the generation of gaps on the microbial wall and surface layer alterations. Ozone can induce significant damage to S. mutans, thus suggesting that the use of ozonated water to prevent carious lesion formation is extremely promising.