G A Reineccius

The Spray Drying of Food Flavors

Abstract Spray drying is the most commonly used technique for the production of dry flavorings. In spray drying, an aqueous infeed material (water, carrier, and flavor) is atomized into a stream of hot air. The atomized articles dry very rapidly, trapping volatile flavor constituents inside the droplets. The powder is recovered via cyclone collectors. Flavor retention is quite satisfactory if dryer operating parameters are properly chosen. Flavor retention is maximized by using a high infeed solids level, high viscosity infeed, optimum inlet (160–210°C) and high exit (>100°C) air temperatures, and high molecular weight flavor molecules. The shelf life of oxidizable flavor compounds is strongly influenced by the flavor carrier.

Flavour-Isolation Techniques

The recovery of aroma compounds from waste streams has been accomplished in only a few commercial applications, the best known being the recovery of coffee or cocoa volatiles during processing. The limitation in application is economics. The waste stream must have an adequate concentration of volatiles and the volatiles must be of high value. Few processing operations meet these economic criteria at this time. In the future, the high costs of recovering flavouring materials from waste streams will be partially offset by the saving in disposal costs associated with environmental issues.

Factors affecting the emulsifying and rheological properties of gum acacia in beverage emulsions

Abstract Gum acacia, a natural hydrocolloid, is extensively used as an emulsifier/stabilizer in beverage emulsions. Factors that may affect emulsion formation, emulsion stability and viscosity of the emulsion concentrate were studied to assess their significance, including proximal composition of the gum (protein content and mineral content), gum processing prior to emulsion preparation (pasteurization and demineralization), and pH of the dilute emulsion. Protein content was not related to emulsion stability, whereas minerals decreased stability presumably due to an electrostatic screening effect. Both pasteurization and demineralization favored stability, most likely by promoting protein unfolding and eliminating the screening effect, respectively. Emulsions were less stable at pH=2.5 than at higher pH levels (4.5 and 5.5). There was a significant difference between the two gum species studied (Senegal and Seyal) in their sensitivity to these treatments. The viscosity of the emulsion concentrate was decreased by pasteurization and increased by demineralization. Protein load at the O/W interface and thickness of the adsorbed layer of emulsifier were not related to emulsion stability. The most important colloidal interactions in dilute beverage emulsions are van der Waals, electrostatic and polymeric steric.

Encapsulation performance of proteins and traditional materials for spray dried flavors

The objective of this study was to evaluate the potential of selected proteins as alternative materials for flavor encapsulation by spray drying. Two traditional materials (gum acacia and modified starch) and three proteins (sodium caseinate, whey and soy protein isolates) were used at different infeed solid levels; test compounds included (R)-(+)-limonene and three alpha,beta-unsaturated aldehydes ((E)-2-hexenal, (E)-cinnamaldehyde, citral). The primary criteria for performance were flavor retention during drying and protection against losses during storage. Limonene oxidation and nonenzymatic browning were investigated as two possible deterioration routes. Overall, higher infeed solids improved retention during drying and limited flavor losses (aldehydes and limonene) during storage in traditional materials only. The materials giving the highest flavor retention during drying were gum acacia (94%), modified starch (88%) and whey protein isolate (87%). Gum acacia provided the highest retention of aldehydes during storage (37 to 58%) after 28 days at 40 degrees C but did not afford good protection against limonene oxidation. Oppositely, protein materials effectively limited limonene oxidation (>70% retained). Nonenzymatic browning was observed for all powders prepared with proteins, especially whey protein isolate, whereas no browning occurred with traditional materials.

Off‐flavors in foods

The most common reason for consumer rejection of a food product is an unacceptable flavor. Food flavor may become unacceptable due to many reasons. For example, the food may become contaminated by airborne-, waterborne-, or packaging-related chemicals. Alternatively, food components may undergo degradation due to oxidation, nonenzymatic browning, enzymatic reactions, or light-induced reactions. This review will provide a general description of the sensory properties, mechanism of occurrence, and recent research developments for the commonly occurring off-flavors in foods.

Storage Life of Pork Chops in CO2-Containing Atmospheres

Pork chops were packaged in a controlled atmosphere (10% CO2/79% N2/1% O2, 30% CO2/68% N2/2% O2, 30% CO2/70% N2, 100% CO2 or air) and then stored at either 2 or 5 C. Changes in gas composition, microbiological counts and sensory quality were monitored after 0, 9, 12, 16, 19, 23, 30 and 37 days of storage. Two chops from each treatment were stored additionally under retail-like conditions for 3 and 5 days. The CO2 percent composition in the packages increased greatly during storage while O2 and N2 showed corresponding decreases. The most effective gas environment in extending sensory acceptability was 100% CO2. The best gas mixtures for extending shelf life at both 2 and 5 C were those containing only CO2 and N2. Sensory data indicated that odor became objectionable before the chops were rejected because of appearance. A temperature increase from 2 to 5 C resulted in greater increases in psychrotroph growth in the control environment (air) than in the CO2 - containing environments. Pseudomonas (oxidase-positive colony count) accounted for 25 - 60% of these counts. The inhibition of microbial growth in the CO2 - containing environments during controlled atmosphere storage appeared to carry over to the rewrap environment.

Influence of Spray-Dryer Air Temperatures on Encapsulated Mandarin Oil

The influence of inlet and exit air temperatures (160–200 and 80–100°C, respectively) on the spray drying of mandarin oil was evaluated by using a three-level factor design. For optimization, dryer evaporative rate, volatile oil retention, and microencapsulation efficiency were considered as response variables. The response surface analysis produced significant (p < 0.05) polynomial regression equations that were successfully fitted for all response variables and no significant (p > 0.05) lack of fit was indicated for the reduced models. This observation confirmed an accurate fitness of the reduced response surface models to the experimental data. The multiple response optimizations indicated that an inlet air temperature of 200°C and an exit air temperature of 80°C were predicted to provide the maximum evaporative rate, volatile oil retention, and microencapsulation efficiency in the studied ranges.

Comparison of modified starch and Quillaja saponins in the formation and stabilization of flavor nanoemulsions.

Modified starch (MS) and Quillaja saponins (QS) were compared to fabricate and stabilize orange oil nanoemulsions using microfluidization. Ester gum (EG) was incorporated in the oil phase at variable proportions (0-60%) as Ostwald ripening inhibitor and viscosity modifier. Optimal viscosity ratios of dispersed to continuous phase (ηd/ηc) were identified as 0.8-3.1 and 2.1-3.3 with MS and QS as emulsifier, respectively. QS was found superior to MS in fabricating nanoemulsion with smallest MDD of 69 nm and turbidity of 102 NTU at 0.05% of dispersed phase. With EG incorporated in the oil phase, QS stabilized nanoemulsions were stable during 2 weeks of storage at 23 °C; whereas MS stabilized nanoemulsions showed significant increases in MDD and turbidity. Zeta potential measurements showed QS imparted higher droplet charge (>-20 mV) than MS (<-5 mV) at pH 3.6 indicating MS stabilized nanoemulsions were destabilized by coalescence due to insufficient interfacial charge.

Modeling the rheology of concentrated beverage emulsions

Abstract A number of theoretical equations were tested against experimental measurements of viscosity of concentrated beverage emulsions in order to model their rheology. Seven samples of gum acacia were used as emulsifiers. All emulsions presented a Newtonian behavior. Best fit corresponded to the Einstein equation, both in its original form and expanded to include short-range colloidal forces. Oil droplets were assumed to be rigid spherical particles, not significantly affected by Brownian motion due to the viscosity of the bulk phase, and subjected to colloidal interactions of limited range.

Interactions Between Wine Matrix Macro-Components and Aroma Compounds

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