Colour is an important quality attribute in the food and bioprocess industries, and it influences consumer’s choice and preferences. Food colour is governed by the chemical, biochemical, microbial and physical changes which occur during growth, maturation, postharvest handling and processing. Colour measurement of food products has been used as an indirect measure of other quality attributes such as flavour and contents of pigments because it is simpler, faster and correlates well with other physicochemical properties. This review discusses the techniques and procedures for the measurement and analysis of colour in food and other biomaterial materials. It focuses on the instrumental (objective) and visual (subjective) measurements for quantifying colour attributes and highlights the range of primary and derived objective colour indices used to characterise the maturity and quality of a wide range of food products and beverages. Different approaches applied to model food colour are described, including reaction mechanisms, response surface methodology and others based on probabilistic and non-isothermal kinetics. Colour is one of the most widely measured product quality attributes in postharvest handling and in the food processing research and industry. Apart from differences in instrumentation, colour measurements are often reported based on different colour indices even for the same product, making it difficult to compare results in the literature. There is a need for standardisation to improve the traceability and transferability of measurements. The correlation between colour and other sensory quality attributes is well established, but future prospects exist in the application of objective non-destructive colour measurement in predictive modelling of the nutritional quality of fresh and processed food products.

Colour Measurement and Analysis in Fresh and Processed Foods: A Review

Anthocyanins are the most abundant flavonoid constituents of fruits and vegetables. The conjugated bonds in their structures, which absorb light at about 500 nm, are the basis for the red, blue and purple colours of fruits, vegetables and their products. Anthocyanin pigments readily degrade during thermal processing which can have a dramatic impact on colour quality and may also affect nutritional properties. This review attempts to summarize some important aspects of anthocyanin degradation during thermal processing. Conclusions regarding the mechanisms and kinetics of anthocyanin degradation during heat treatment are postulated based on current findings.

Effect of thermal processing on anthocyanin stability in foods; mechanisms and kinetics of degradation

Statistical Databases

The thin-layer drying characteristics of garlic slices

Consumers increasingly demand convenience foods of the highest quality in terms of natural flavor and taste, and which are free from additives and preservatives. This demand has triggered the need for the development of a number of nonthermal approaches to food processing, of which high-pressure technology has proven to be very valuable. A number of recent publications have demonstrated novel and diverse uses of this technology. Its novel features, which include destruction of microorganisms at room temperature or lower, have made the technology commercially attractive. Enzymes and even spore forming bacteria can be inactivated by the application of pressure-thermal combinations, This review aims to identify the opportunities and challenges associated with this technology. In addition to discussing the effects of high pressure on food components, this review covers the combined effects of high pressure processing with: gamma irradiation, alternating current, ultrasound, and carbon dioxide or anti-microbial treatment. Further, the applications of this technology in various sectors— fruits and vegetables, dairy, and meat processing—have been dealt with extensively. The integration of high-pressure with other matured processing operations such as blanching, dehydration, osmotic dehydration, rehydration, frying, freezing / thawing and solid-liquid extraction has been shown to open up new processing options. The key challenges identified include: heat transfer problems and resulting non-uniformity in processing, obtaining reliable and reproducible data for process validation, lack of detailed knowledge about the interaction between high pressure, and a number of food constituents, packaging and statutory issues.

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Opportunities and Challenges in High Pressure Processing of Foods

Mass-Volume-Area-Related Properties of Foods Mohammad Shafiur Rahman Surface Properties Karl F. Schilke and Joseph McGuire Food Microstructure Analysis Bryony James Glass Transition in Foods Jasim Ahmed and Mohammad Shafiur Rahman Rheological Properties of Fluid Foods M. A. Rao Rheological Properties of Solid Foods V. N. Mohan Rao and Ximena Quintero Thermal Properties of Unfrozen Foods Paul Nesvadba Thermal Properties of Frozen Foods Gail Bornhorst, Arnab Sarkar, and R. Paul Singh Properties Relevant to Infrared Heating of Food Ashim K. Datta and Marialuci Almeida Mass Transfer Properties of Foods George D. Saravacos and Magda Krokida Thermodynamic Properties of Foods in Dehydration S. S. H. Rizvi Physicochemical and Engineering Properties of Food in Membrane Separation Processes Dipak Rana, Takeshi Matsuura, and Srinivasa Sourirajan Electrical Conductivity of Foods Sudhir K. Sastry and Pitiya Kamonpatana Dielectric Properties of Foods Ashim K. Datta, G. Sumnu, and G.S.V. Raghavan Ultrasound Properties of Foods M. J. McCarthy, L. Wang and K. L. McCarthy Kinetic Data for Biochemical and Microbiological Processes during Thermal Processing Ann Van Loey, Stefanie Christiaens, Ines Colle, Tara Grauwet, Lien Lemmens, Chantal Smout, Sandy Van Buggenhout, Liesbeth Vervoort, and Marc Hendrickx Kinetics and Process Design for High-Pressure Processing Tara Grauwet, Stijn Palmers, Liesbeth Vervoort, Ines Colle, Marc Hendrickx, and Ann Van Loey Gas Exchange Properties of Fruits and Vegetables Bart M. Nicolai, Jeroen Lammertyn, Wendy Schotsmans, and Bert E. Verlinden

Engineering Properties of Foods

Polylactide (PLA), a biodegradable aliphatic polyester, has been studied extensively for its wide applications in various fields from food packaging to interior materials for automobiles. One of PLA's advantages is that the raw material, lactic acid can be derived from renewable resources, which makes PLA very attractive for the packaging and considered as green packaging. Although, the cost of PLA is relatively higher compared to petroleum based packaging materials and it is predicted that the price will go down after commercial success of the process. This paper presents a review on polylactide with focus on its chemistry, synthesis, properties, and applications. Plasticization effect on PLA, sorption isotherm and mechanical properties of PLA based packaging materials have been discussed. PLA/layered organo nanocomposites exhibit significant improvement in mechanical, thermal, optical, and physicochemical properties over pure PLA. This review includes brief overview of PLA based nanocomposite, their mec...

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Polylactides—Chemistry, Properties and Green Packaging Technology: A Review

Thermo-mechanical, rheological, structural and antimicrobial properties of bionanocomposite films based on fish skin gelatin and silver-copper nanoparticles

Physico-chemical, rheological, calorimetric and dielectric behavior of selected Indian honey



The degradation kinetics of carotenoids and visual color of papaya puree were investigated at selected temperatures (70 to 105°C). The concept of fractional conversion was applied to determine the kinetic parameters. The degradation of papaya color was based on change of Hunter a and b values and it was found that combination of Hunter (a × b) value adequately represented thermal color change. Degradation of carotenoids and visual color followed first order reaction kinetics. Dependence of the rate constant followed the Arrhenius relationship. The process activation energies for carotenoids and visual color were 20.56 and 32.59 kJ/mol respectively. Higher activation energy value indicated greater temperature sensitivity of visual color as compared to carotenoids. The degradation of pigment and visual color varied linearly. Visual color could therefore be used for on-line quality control of papaya puree.

Jasim Ahmed

Papers

Engineering Properties of Foods

Polylactides—Chemistry, Properties and Green Packaging Technology: A Review

Thermo-mechanical, rheological, structural and antimicrobial properties of bionanocomposite films based on fish skin gelatin and silver-copper nanoparticles

Physico-chemical, rheological, calorimetric and dielectric behavior of selected Indian honey

Thermal Degradation Kinetics of Carotenoids and Visual Color of Papaya Puree