Ricardo Simpson

Development of an ingredient containing apple peel, as a source of polyphenols and dietary fiber.

Apple peel is a waste product from dried apple manufacture. The content of phenolic compounds, dietary fiber, and mineral are higher in apple peel, compared to other edible parts of this fruits. The objective of this study was to develop an ingredient from Granny Smith apple peel, using a pilot scale double drum-dryer, as drying technology. The control of all steps to maximize the retention of phenolic compounds and dietary fiber was considered. Operational conditions, such as drying temperature and time were determined, as well as important preprocessing steps like grinding and PPO inhibition. In addition, the physical-chemical characteristics, mineral and sugar content, and technological functional properties such as water retention capacity, solubility index, and dispersability among others, were analyzed. A simple, economical, and suitable pilot scale process, to produce a powder ingredient from apple peel by-product, was obtained. The drying process includes the application of ascorbic acid at 0.5% in the fresh apple peel slurry, drum-dryer operational conditions were 110 degrees C, 0.15 rpm and 0.2 mm drum clearance. The ingredient developed could be considered as a source of phenolic compounds (38.6 mg gallic acid equivalent/g dry base) and dietary fiber (39.7% dry base) in the formulation of foods. Practical Application: A method to develop an ingredient from Granny Smith apple peel using a pilot scale double drum-dryer as drying technology was developed. The method is simple, economical, feasible, and suitable and maximizes the retention of phenolic compounds and dietary fiber present in the raw matter. The ingredient could be used in the formulation of foods.

An unsteady-state method to determine kinetic parameters for heat inactivation of quality factors: Conduction-heated foods

Abstract The kinetic parameters (D121·1°C and z values) for the heat inactivation of a quality factor in conduction-heated canned food were evaluated by using the Complex optimization procedure and a numerical technique for heat-transfer calculations and quality-retention prediction. The jackknife method was used to evaluate experimental variability. This methodology was used to determine the D121·1°C and z values for thiamine destruction in pea puree (pH = 6·8, moisture content=80·8%, and thermal diffusivity, α = 1·8 × 10−7 m2/s). Retort-processing experiments involving the use of 303 × 406 cans filled with thiamine-enriched pea puree yielded a wide range of thiamine-retention values (29–70%). The D121·1°C and z values obtained were 304 ± 32 min and 30 ± 3°C, respectively.

Mathematical models and logic for the computer control of batch retorts: Conduction-heated foods

Abstract A computer program was developed to implement a mathematical model to control on-line batch retort operations for conduction-heated foods. The model is based on a numeric solution for heat transfer in cylindrical cans. The heat transfer equation was solved using a numeric method with a variable grid. Integrated lethality values are calculated assuming first-order kinetics for microbial inactivation, taking into account the cumulative lethality of the heating and cooling period. The program adjusts process time automatically to compensate for any unexpected variation in retort temperature, and was validated using processes reported in the literature. The computational speed of the numeric method described could be applied to other calculation-intensive simulations.

A Comparative Study of Stout Beer Batch Fermentation Using Free and Microencapsulated Yeasts

Because many questions arise regarding the use of immobilization technology to consistently produce a high quality beer, this work focuses on the effects of using an immobilization matrix in the fermentation process. The aim of this study was to explore the feasibility and potential uses of immobilization on sensorial characteristics such as color, flavor, and headspace compounds of stout beer, when using batch fermentation. Batch production of beer was conducted as a standard ale process for stout beer production. For the immobilized yeasts fermentation, cells were microencapsulated in alginate, by using the Thiele modulus procedure for microcapsule design. Glucose concentration, cell multiplication, cell viability, specific gravity, pH, Brix, and ethanol were monitored throughout the fermentation process. Both, sensorial analysis (statistic triangle tests) and instrumental methods (gas chromatography to measure headspace compounds and visible spectrophotometer to quantify the color) were used to evaluate characteristics of the beer that was produced from immobilized and free yeast fermentations. Free and immobilized yeasts fermentation showed no significant difference (p > 0.05) for all variables of interest. The profile of headspace compounds was different, perhaps because of changes in yeast’s behavior and the presence of secondary metabolites. However, immobilization did not have a significant impact on the beer flavor, as detected by the sensorial triangle test.

Time-Temperature Effects on Microbial, Chemical and Sensory Changes During Cooling and Aging of Cheddar Cheese

Cheddar cheese requires several months of aging, during which operating costs and interests on capital significantly add to production costs. The flavor and aroma of aged Cheddar cheese is attributed to a complex mixture of chemical compounds (Lawrence and Gilles, 1987) which is influenced by the cheese microflora. The microflora consists of starter bacteria which reach maximum levels during cheese making and bacteria present in the milk after heat treatment or introduced during manufacturing (Chapman and Sharpe, 1981). Both starter and non-starter activity contributes extensively to finished cheese quality (Gilles and Lawrence, 1973; Fryer, 1982; Lawrence et al., 1983, 1984; Law, 1984). The temperature of the post hoop cheese block ranges between a high of 35°C at pressing to an aging temperature of 3.5-12°C. During the cooling period, a temperature gradient is established within the block of cheese. The extent of chemical and microbial activities at any given point within a cheese block will depend, in part, on the temperature profile over time at that point. Sensory characteristics and including textural parameters will reflect the extent of these activities.

Optimization of Food Thermal Processing: Sterilization Stage and Plant Production Scheduling

Two optimization problems that have arisen in thermal process calculation are considered in this chapter. First, there is the problem of thermal process calculation where process time at a specified retort temperature must be calculated to achieve safe levels of microbial inactivation (lethality). Second, there is the problem of determining an optimized scheduling at food canneries using several autoclaves (not necessarily the same capacity), to sterilize given amounts of different canned food products with specific quality requirements.

Mathematical Estimations of Impact of Thermal Processing on Microbial Inactivation and Quality Retention

The basic principles of canning have not changed dramatically since Nicholas Appert and Peter Durand developed the process. The sterilization and pasteurization of foods have a long tradition, and this tradition will likely continue due to its convenience and advances in the technology as well as the packaging materials. Mathematical modeling has been gaining recognition in the food industry, particularly for applications such as thermal sterilization and pasteurization, helping the food industry to deliver safe processed products that also retain quality to a greater extent. In recent years, several researchers have been developing applications for multiobjective optimization in food processing, especially in the area of thermal food sterilization.

Basic Economic Principles and Deciding Among Alternatives

The purpose of this chapter is to familiarize you with the concept of interest rate (or the time value of money) and then give you the capability to manage simple but engaging decision-alternative problems related to real-life situations and process engineering. We will keep it simple in terms of economic concepts, but you will be considering interesting situations from everyday life and, additionally, stimulating and thought-provoking problems related to chemical and bioprocess engineering. We will continue learning about and engaging with the broad field of process and bioprocess engineering. Through the problems in the chapter, you will become familiar with various options for loans and how to compare them and improve your behavior as a rational consumer. The core of this chapter will focus on problems where you, as an engineer, need to compare different alternatives and make decisions mainly based on economic considerations. You will encounter questions where your technical expertise and knowledge of economics will be challenged to compare, for example, proposals from two or more companies to replace reactors at a processing plant. At this stage the problems will focus on economic analysis. For us, though, as future process and bioprocess engineers, the technical aspects of the project are more relevant, so we will leave this matter for future courses.

Fundamentals of Magnitudes, Unit Systems, and Their Applications in Process Engineering

Most students, at various levels, are Probably familiar with unit systems. In this chapter, we provide some details of the International System of Units and its relation to the English Engineering system. Our main purpose is to ensure that students cannot only use different systems but also convert units among different systems. In addition, students will gain an understanding of the different approximate dimensions and sizes that occur frequently in the field of chemical and bioprocess engineering.

Learning from Nature and Its Potential Applications in Chemical and Bioprocess Engineering

It is possible that most, if not all, of the problems that an engineer will want to solve now and in the near future may already have been solved by nature, although in a different context.