Storage stability of potato variety Lady Rosetta under comparative temperature regimes

Potatoes are usually stored under low temperatures for sprout prevention and to ensure their continuous supply. Low temperature sweetening in potato is the major temperature related disorder being faced by the growers and is also known to be associated with variety specific storage temperature. The present study aimed at identifying the appropriate storage temperature for the premium potato variety Lady Rosetta with special reference to the changes in its quality attributes, that is weight loss, total sugars, starch, ascorbic acids, total phenolic contents, radical scavenging activity, enzymatic activities and potato chip color. The selected potato variety was stored under different temperature (5, 15 and 25oC) regimes to identify appropriate storage temperature. Our results showed significant variations in the tested quality attributes in response to different storage temperatures. Storage at 5oC maintained tuber dormancy up to 126 days, however, found associated with increased sugar accumulation (2.32 g/100 g), rapid starch depletion (13.25 g/100 g) and poor post processing performance (L-value, 52.00). In contrast, potato storage at 15oC retained lower sugar contents (1.33 g/100g) and superior chip color (L-value, 59.33) till the end of storage. However, they were found associated with the increased polyphenol oxidase (38.47 U/g f.w) and peroxidase (15.25 U/100 g f.w) activities as compare to those potatoes stored at 5oC during the same storage period. Storage life of potato tubers at 25oC was significantly reduced due to dormancy break on 84th day and subsequent starch degradation (15.29 g/100 g) increased sugar accumulation (1.32 g/100 g) and increased polyphenol oxidase (79.89 U/g f.w) and peroxidase activities (40.69 U/100 g f.w). Our results showed that potato variety Lady Rosetta is cold sensitive and requires specific temperature for prolonged storage and best post processing performance

Inductively coupled Ar/Clâ‚‚ plasma etching of GaN

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Ascorbic acid encapsulation in a glassy carbohydrate matrix via hot melt extrusion: Preparation and characterization

Abstract Hot melt extrusion technology using a twin-screw extruder was employed to obtain maltodextrin, maltodextrin-gum arabic and maltodextrin-trehalose based glassy extrudates containing ascorbic acid (dispersed phase). Ascorbic acid payload of all three formulations was more than 15.67 g/100 g extrudates while the ascorbic acid yield was above 97%. The glass transition temperature (Tg) of all extrudates was above 40 °C. The expansion ratio of the extrudates and Tg reduced due to the incorporation of trehalose and gum arabic to maltodextrins, respectively. The results of Scanning Electron Microscopy, X-ray diffraction and Fourier-transform Infrared Spectroscopy confirmed that the formulated feed material turned into a glassy state, whereas, ascorbic acid was uniformly dispersed throughout the glassy matrix. Extruded formulations showed a steady dissolution rate, therefore, having a role in controlling the dissolution rate of ascorbic acid

Stable Nanoparticles Prepared by Heating Electrostatic Complexes of Whey Protein Isolate–Dextran Conjugate and Chondroitin Sulfate

A simple and green method was developed for preparing the stable biopolymer nanoparticles with pH and salt resistance. The method involved the macromolecular crowding Maillard process and heat-induced gelation process. The conjugates of whey protein isolate (WPI) and dextran were produced by Maillard reaction. The nanoparticles were fabricated by heating electrostatic complexes of WPI–dextran conjugate and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. Then, the nanoparticles were characterized by spectrophotometry, dynamic laser scattering, zeta potential, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Results showed that the nanoparticles were stable in the pH range from 1.0 to 8.0 and in the presence of high salt concentration of 200 mM NaCl. WPI–dextran conjugate, WPI, and ChS were assembled into the nanoparticles with dextran conjugated to WPI/ChS shell and WPI/ChS core. The repulsive steric interactions, from both dextran covalently conjugated to WPI and ChS electrostatically interacted with WPI, were the major formation mechanism of the stable nanoparticles. As a nutrient model, lutein could be effectively encapsulated into the nanoparticles. Additionally, the nanoparticles exhibited a spherical shape and homogeneous size distribution regardless of lutein loading. The results suggested that the stable nanoparticles from proteins and strong polyelectrolyte polysaccharides would be used as a promising target delivery system for hydrophobic nutrients and drugs at physiological pH and salt conditions

Modelling and Kinetic Study of Novel and Sustainable Microwave-Assisted Dehydration of Sugarcane Juice

Sugarcane juice is a perishable food with a good nutritional profile. Thus, there is a need to increase its shelf life by reducing water content which facilitates storage and transportation. In this study, process conditions were optimized to concentrate the sugarcane juice at various microwave powers (30, 50, 80, 100 W). A central composite design was applied to optimize the process conditions (power and time). The overall evaporation time depends on microwave powers; increase in power reduced the processing time. The results showed that at 100 W sugarcane juice was concentrated to 75° brix for 15 min which reduced the energy consumption to 1.3 times compared to other powers. Moreover, microwave processing better retained the sensory properties of concentrate and preserved its antioxidant activity. Thus, 100 W was most energy efficient in concentrating sugarcane juice. In general, microwave processing reduced the processing time and cost making it a sustainable approach to concentrate juices

Antibiotics, Acid and Heat Tolerance of Honey adapted Escherichia coli, Salmonella Typhi and Klebsiella pneumoniae

The medicinal importance of honey has been known for many decades due to its antimicrobial properties against life-threatening bacteria. However, previous studies revealed that microorganisms are able to develop adaptations after continuous exposure to antimicrobial compounds. The present study was conducted to explore the impact of subinhibitory concentrations of branded honey (Marhaba) and unbranded honey (extracted from Ziziphus mauritiana plant) locally available in Pakistan on Escherichia coli ATCC 10536, Salmonella Typhi and Klebsiella pneumoniae by investigating the development of self- or cross-resistance to antibiotics (gentamicin, kanamycin and imipenem). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of autoclaved honeys were determined. The bacterial cells of E. coli ATCC 10536, S. Typhi and K. pneumoniae were subjected to honey adaptation by exposing to ¼ × MIC (4 passages) and ½ × MIC (4 passages) of both honeys. Moreover, tolerance to low pH and high temperature was also studied in adapted and unadapted cells. The decreasing trend in growth pattern (OD600nm) of E. coli ATCC 10536, S. Typhi and K. pneumoniae was observed with increases in the concentration of honeys (6.25–50% v/v) respectively. Our results showed that continuous exposure of both honeys did not lead to the development of any self- or cross-resistance in tested bacteria. However, percent survival to low pH was found to be significantly higher in adapted cells as compared to unadapted cells. The results indicate that both branded honey (Marhaba) and unbranded honey (extracted from Ziziphus mauritiana plant) were effective in controlling the growth of tested pathogenic bacteria. However, the emergence of tolerance to adverse conditions (pH 2.5, temperature 60 °C) deserves further investigation before proposing honey as a better antibacterial agent in food fabrication/processing, where low pH and high temperatures are usually implemented