Franco Pedreschi

Pontifical Catholic University of Chile | UC · Departamento de Ingeniería Química y Bioprocesos

Southern Chile native potatoes are an interesting raw material to produce novel snacks like colored potato chips. These novel products should be comprehensively evaluated for the presence of undesirable compounds such as acrylamide, 5-hydroxymethylfurfural and furan, the main neoformed contaminants in starchy rich fried foods. This study evaluated...

Colored potatoes have been of interest because of their nutritional and health-promoting properties. However, their aptitude for processing regarding acrylamide formation levels is highly variable and for the most part unknown. In this work, the effect of cultivation season (summer and winter), and postharvest cold storage (1, 2, and 5 months at 5...

The problem of processing contaminants is now one of the most challenging issues the food industry needs to address. Heat processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, and they are not present or present at much lower concentrations in the raw, unprocessed food. These heat toxic com...

The rational design of methodologies to control the neoformed compounds occurrence (NFCs), such as acrylamide and hydroxymethylfurfural (HMF) in roasted coffee, must consider the preservation of the bioactive compounds contained in this beverage. The aim of this work was to evaluate the integrated effect of yeast inoculation during the fermentation...

A 2k factorial design with three centrals points was considered to evaluate the effect of adding red Tara pods extract (Caesalpinia spinosa) (440-2560 µg/mL of dough water) and NaCl (0.3-1.7 g/100 g of flour) on the acrylamide (AA) and hydroxymethylfurfural (HMF) content and sensory attributes of crackers. Additionally, the best formulation, define...

s Background Neo-formed contaminants (NFCs) occurrence in coffee, a highly consumed beverage worldwide, has raised concern among different food safety agencies because a high intake of these toxic compounds may represent a long-term risk for the consumer health. The mechanisms responsible of NFCs formation in roasted coffee also trigger the genera...

Brown seaweed phlorotannins have shown the potential to promote several health benefits. Durvillaea incurvata and Lessonia spicata—species that are widely distributed in central and southern Chile—were investigated to obtain phlorotannin extracts with antioxidant and antihyperglycemic potential. The use of an environmentally friendly and food-grade...

The effect of ultrasound (480 W, 40 kHz) on the leaching of reducing sugars during the water soaking of potatoes slices (60, 70 and 80 °C- 1, 8 and 15 min) was investigated to reduce the formation of acrylamide (AA) and 5-hydroxymethylfurfural (5-HMF) in potato chips. Ultrasound (US) influenced abruptly the reducing sugar leaching during the first...

This study estimates for the first time dietary acrylamide intake in Chile and conducts exposure risk assessments using the margin of exposure (MOE) method. A consumption frequency survey of starchy foods was carried out in the metropolitan region of Santiago, Chile on people from different socioeconomic levels aged between 12 and 65 years old. The...

This work assessed the effect of formulation and heat treatment on the formation of HMF, non-enzymatic browning and rheology of dulce de leche (DL). Laboratory scale trials were developed with different DL formulas: whole powdered milk, skimmed milk, and lactose-free skimmed milk, and added sucrose, subjected to different processing temperatures (1...

In this work an HPLC-DAD determination method for free and total HMF in "dulce de leche" was developed and validated. The separation was carried out using a mobile phase of acetonitrile-water (4.5:95.5, v/v) on Acclaim™120 C18 (4.6 × 150 mm, 5 μm), at 30 • C and a flow rate of 1 mL/min. The detection was done at 284 nm.The method showed good select...

Sequential extraction and purification stages are required to obtain extracts rich in specific polyphenols. However, both separation processes are often optimized independently and the effect of the integrated process on the global recovery of polyphenols has not been fully elucidated yet. We assessed the impact of hot-pressurized liquid extraction...

Rose hip is of great interest among food manufacturers and consumers because it contains compounds that give it a high antioxidant capacity. To determine the effect of the frozen storage process over the vitamin C content, total phenols, antioxidant capacity, linolenic acid, linoleic acid, and other properties, rose hip pulp was stored at –5°C, –10...

The aim of this paper is to test different models for predicting furan content in a dough system, based on partial least squares regression using colour images. Starch dough systems were fried at five temperatures between 150 and 190 °C and for 5, 7, 9, 11 and 13 min. The furan content was quantified using gas chromatography/mass spectrometry, whil...

The industrial quality index was monitored in frozen industrial burgers (peroxide value, thiobarbituric acid, redness, instrumental texture, total volatile basic nitrogen, and weight loss) stored at four temperatures. Kinetics was modeled by fitting the Weibull model equation, and the corresponding empirical kinetic rates were calculated. As the fr...

“Hallulla” is a highly consumed type of Chilean bread, which may contain considerable amounts of some Neo-Formed Contaminants (NFCs). The objective of this research was to study the effect of tara (Caesalpinia spinosa) pod polyphenolic extract (TPPE) on the mitigation of acrylamide (AA) and hydroxymethylfurfural (HMF) in “hallulla” bread without af...

Browning kinetic was quantified in two types of pita bread based on the resulting color heterogeneity formed on their surface due to toasting them at four different temperature states (160, 180, 200, and 220 °C correspondingly). In the browning kinetic description, a fractal method was used. The fractal method measures color intensity resulting fro...

Hot pressurized liquid extraction has been used to obtain polyphenols; however, its operating conditions can generate hydroxymethylfurfural, a potential human carcinogen. The addition of ethanol can reduce process temperatures and retain extraction efficiencies, but the ethanol may reduce the recovery of polyphenols in the subsequent purification s...

Thermal degradation and generation of objectionable compounds such as hydroxymethylfurfural have been observed in hot pressurised water extraction of polyphenols. Addition of small amounts of ethanol can reduce process temperatures and retain extraction efficiencies. However, ethanol may reduce the recovery of polyphenols in the subsequent purifica...

Consumers like fried snacks, and taste, color, and texture are key aspects in their preference. However, during frying of foods some toxic compounds, such as furan and acrylamide, are produced. The objective of this work was to mitigate furan and acrylamide formation in potato chips, without affecting their main quality attributes, by using vacuum...

This research tested furan classification models in fried matrices based on the pattern recognition of images. Samples were fried at 150, 160, 170, 180, and 190°C for 5, 7, 9, 11, 13, and 30 min. Furan was measured by GC–MS. Corresponding images were acquired and processed to extract 2175 chromatic and textural features. Principal component analysi...

Acrylamide (AA) (CAS number 79-06-1) (CH2=CH–CO–NH2), a white, odorless, toxic crystalline compound is produced mainly for the synthesis of nontoxic polyacrylamide, which is used as a flocculent in water treatment, and as a binder in pulp and paper processing. AA affects the nervous system even at low levels, causing hallucinations and drowsiness (...

Potato processing is highly industrialized, technologically advanced, and very market-driven. However, the quality of its products and the economic success of this industry highly depend on available raw materials: namely, the potatoes. Deep fat frying is a complex unit operation that induces significant microstructural changes in potato tissue; in...

Yucca schidigera Roezl. (yucca) is one of the major industrial sources of steroid saponins used as animal and human food additives. This work describes a new, systematic and reproducible three-step method by medium and high-pressure liquid chromatography (under RP, NP and RP conditions), for the isolation and purification of three groups of saponin...

Furan is a possible human carcinogen, which is formed in worldwide highly consumed fried starchy foods. In order to elucidate the mechanisms responsible for its occurrence in this food category and propose techniques for its mitigation, the kinetics of furan formation, oil absorption, lipid oxidation, and color change were studied in wheat flour-ba...

Yucca schidigera Roezl. (yucca) is one of the major industrial sources of steroid saponins approved by the FDA as GRAS (Generally Recognized As Safe). Due to the increasing applications of yucca extracts, there is a need for a simple, low-cost method for the authentication of samples. This paper presents a method to obtain unique fingerprints of co...

This study was focused on a comparison between the first order model and the Weibull model regarding their suitability to fit the enzymatic browning kinetic data in samples of mushrooms, pears, apples, avocados, and bananas (based on the use of the L* luminosity, the ΔE*, and the BI as the browning indexes). In order to obtain statistically robust...

FoodDrinkEurope Federation recently released the latest version of the Acrylamide Toolbox to support manufacturers in acrylamide reduction activities giving indication about the possible mitigation strategies. The Toolbox is intended for small and medium size enterprises with limited R&D resources, however no comments about the pro and cons of the...

Poly(lactid acid) (PLA) is one of the biopolymers that have gained major interest to replace the use of polymer petroleum derived [1]. However brittleness and other properties such as low thermal stability, medium gas barrier properties and low solvent resistance (e.g., against water) of the pure polymer are often insufficient for food packaging ap...

Increasing amounts of non-biodegradable plastic ends up accumulated in landfills at their end-of-life causing a major environmental concern for modern society. Compostable polymers such as poly(lactic acid) (PLA) have been used to avoid landfill disposal, but they tend to provide poor mechanical, physical and barrier properties. Natural nanoclays s...

Starch granules imbibe water and swell when exposed to abundant water and temperatures above their gelatinization point. The degree of gelatinization of four native starches, wheat, potato, cassava and corn, was determined by the enthalpic transitions and simultaneous events between loss of birefringence and swelling to quantify the process in situ...

The occurrence of furan in home cooked food was studied. Cooking was found to reduce the level of furan in ready-to-eat foods, however on average around 50% of furan remain in the foods. The analysis of furan occurrence revealed that it is most commonly formed in foods with high levels of carbohydrates. Interestingly, breakfast cereals, dry bread p...

Deep-frying is a common multifunctional unit operation for fast drying, texturing and cooking of foods. Deep-fat frying is a rather complex process comprising simultaneous heat and mass transfer with chemical reactions and textural changes taking place. The high temperatures of the frying affect surface colour and mechanical characteristics of frie...

Introduction and Objectives: The increase of bacterial resistance to antibiotics and the efforts to develop natural preservatives in food manufacturing have increased the interest in the application of essentials oils and naturals compounds with antimicrobial properties. Several studies report the antimicrobial capacity of single compounds, but not...

Browning reaction variability in apple slices was characterized using a new procedure denominating the differential pixel method. Using this method, a kinetic rate and an empirical order of reaction were derived for each pixel in an image corresponding to a sliced apple surface undergoing browning; each pixel in the image can be seen as a small por...

Edible films (EF) have been investigated as food packaging, since it would be beneficial to reduce the environmental impact associated with synthetic films. Polysaccharides and proteins create a network responsible for good mechanical properties, however, their inherent hydrophilic nature leads to high water vapor permeabilities. One approach to de...

Acrylamide (AA) is known as a neurotoxin in humans and it is classified as a probable human carcinogen by the International Agency of Research on Cancer (IARC, 1994). AA is produced as by-product of Maillard reaction in starchy foods processed at high temperatures (> 120 °C). This review includes the investigation of AA precursors, mechanisms of AA...

Color stability of fresh meat gives an idea about possible consumer preferences based on the appearance of the product, and it is an important property that influences its market value and the consumer's purchase decision. Color changes on the surface of fresh cut meat were evaluated applying fractal kinetic analysis based on the redness color valu...

El objetivo de este estudio es determinar la concentración mínima inhibitoria de tres compuestos antimicrobianos naturales (citral, carvacrol y eugenol) frente a Listeria inocua y Escherichia coli, para posteriormente ser incorporarlos en una película biodegradable como recubrimiento de alimentos.

The increasing consumption worldwide of tortilla chips make it relevant to design and optimize their industrial quality analysis. Surface, structural, and total oil content during frying of tortilla chips fried at 160, 175, and 190 degrees C for different times were analyzed. The aim was to obtain a relationship between oil content and features fro...

Chilean consumer preferences include foods that may contain considerable amounts of furan, a potential human carcinogen. However, there is no information regarding dietary exposure to furan in Chile. Thus, the objective of this work was to determine the Chilean exposure to dietary furan. To accomplish this objective, the furan concentration of 14 t...

The presence of furan in a broad range of heat processed foods (0-6000 μg kg(-1)) has received considerable attention due to the fact that this heat induced contaminant is considered as a "possible carcinogenic compound to humans". Since a genotoxic mode of action could be associated with furan-induced tumor formation, current human exposure levels...

The study of the equilibrium is needed not only for modeling of the osmotic process as a unit operation but also for a better understanding of the mass transfer mechanisms involved in this kind of systems. A true equilibrium state usually takes very long time to achieve; therefore, a pseudo-equilibrium state is often employed. Experimental pseudo-e...

Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation wi...

Considerable research efforts in computer vision applied to food quality evaluation have been developed in the last years; however, they have been concentrated on using or developing tailored methods based on visual features that are able to solve a specific task. Nevertheless, today’s computer capabilities are giving us new ways to solve complex c...

Deep-fat frying is a unit operation which develops unique sensorial attributes in foods. For instance, texture is the principal quality parameter of tortilla and corn chips. On the other hand, computer vision is a useful tool for quality evaluation and prediction of some physical properties in different either raw or processed foods. The objective...

Frying is one of the oldest unit operations and is used not only in industry but also at home. The most commonly fried vegetable is potato, for important commercial products such as potato chips, par-fried potatoes, and french fries. Quality parameters of interest for fried potatoes include physical and chemical properties such as color, mechanical...

In this research the automatic classification of commercial potato chips by computer vision was studied. The general objective was to design a tool that would be able to classify objectively potato chips according to their color in different categories. For this purpose, sensory measurements of color in 100 potato chips were correlated with the cor...

Heating foods has many advantages since it adds taste, color, texture and minimizes harmful germs, among others. Flavor and aroma compounds are produced via the Maillard reaction, where various hazardous compounds may form as well, such as acrylamide. Maillard reaction is believed to be the main route for acrylamide formation between reducing sugar...

Potato chips were classified in quality categories according to their color after frying at oil temperatures (120, 140, 160, and 180 ± 1 °C) and undergoing some pre-treatments (control or unblanching, blanching, and blanching plus drying). For each oil temperature, six time intervals were considered since the beginning of the frying process until t...

Modelling of browning is essential to evaluate the effectiveness of the processes applied to obtain fresh-appearance foods and also to determine their shelf life. Computer vision and the fractal kinetic method were used to quantify browning in three avocado cultivars. Samples (avocado slices and purée) were stored at 4 °C and surface images were ca...

In April 2002, Swedish researchers shocked the world when they presented preliminary findings on the presence of acrylamide in fried and baked foods, most notably potato chips and French fries, at levels of 30–2,300ppb. The objective of this research was to study the effect of immersing potato slices in a NaCl solution over the acrylamide formation...

Polymer science approach has shown to be useful to understand the structural complexity of food systems. This work looks at the effect of glycerol (5%, 10%, and 20% (dry weight basis)) on the glass transition temperature (Tg) of a starchy matrix determined by DSC and its prediction using Ten-Brinke–Karasz equation. Waxy maize starch (WMS) and rice...

A computer vision method was developed and used to assign color score in salmon fillet according to SalmonFan™ card. The methodology was based on the transformation of RGB to L*a*b* color space. In the algorithm, RGB values assigned directly to each pixel by the camera in the salmon fillet image, were transformed to L*a*b* values, and then matched...

The use of edible films to coat food products is a technique that allows for an extended shelf-life. One of the most widely used polymers is calcium alginate. However, this polymer can modify the original food color and the perception by consumers. The objective was to design an alginate film based principally on color changes using a RGB color mod...

a b s t r a c t The contents of dry matter, oil and acrylamide are some of the most relevant parameters in the quality control of potato chips. Near infrared spectroscopy (NIR) is a common technique for routine analysis of bulk chemistry in different raw materials and products because it allows a fast and non-destructive anal-ysis of samples. The o...

The modeling approach to predict the sorption behavior of nonelectrolytic mixtures has been related to moisture content at a specifi c equilibrium relative humidity (ERH) and to the component weight fraction in the system. The work presented here attempts to identify deviations of the predicted sorption profi le of a model system based on rice star...

In this chapter book, we present and discuss some aspects of hydrocolloid edible films and coating. The film-forming materials is presented and the physical properties (e.g. thickness, mechanical, optical and thermodynamic properties, water and gases barrier) of the film and coating are examined in detail. The main techniques used to form edible co...

The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desirée and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water a...

Potato is one of the most important processed vegetables. Frying and dehydration are important unit operations used commonly by industry to process potatoes. Oil uptake and acrylamide content are major issues in fried potatoes related to the health and safety of consumers. Oil uptake in fried potatoes diminishes as the frying temperature increases....

A novel methodology “fractal browning indicator” (FBI) is presented, that describes the enzymatic browning kinetic based on the use of irregular color patterns from banana slice images. It uses the fractal Fourier texture image value in a selected area, to calculate a fractal dimension (FD), which represents the complexity of color distribution. Du...

In food fermentation, many types of immobilization systems are used, such as hydrogel entrapment, where alginate is the main biopolymer. one of the important problems in industrial processes is the quantifications of biomass, since the traditional system of direct cell counting cannot be used. In this study, a simple digital imaging method to deter...

The objective of this research was to determine the kinetics of water loss and oil uptake during frying of pre-treated potato slices under vacuum and atmospheric pressure. Potato slices (diameter: 30 mm; width: 3 mm) were pre-treated in the following ways: (i) raw potato slices “control”; (ii) control slices were blanched in hot water at 85 °C for...

a b s t r a c t A new approach (FBI) describing the enzymatic browning kinetics for three apple cultivars, is presented. It is based on quantification of the irregular color patterns that emerge from the apple surface during enzymatic browning, rather than using the color average in the same area analyzed. In the experiments, three apple cultivars...

Kinetics of extraction of reducing sugars from potato slices was studied during blanching. Two models based on Fick’s law were used to describe loss of reducing sugars during blanching at 60, 75 and 90 °C. The first one is the classic model with a constant effective reducing sugar diffusion coefficient. The second model considers that the diffusion...

Potato is the raw food material that has been used the most in frying operations due to the high demand of consumers all over the world. Detection of high concentrations of acrylamide in heated starch rich foodstuffs, such as potato, by the Swedish National Food Administration in April 2002 attained public concern because this product is a suspecte...

Grading and sorting of potatoes ensure that derived products meet the defined grade requirements for sellers and the expected quality for buyers. Grading is particularly important for potatoes because the size, shape, color, and defects depend greatly on environmental conditions and handling and is performed primarily by trained human inspectors wh...

This chapter summarizes the application of computer vision to study the quality attributes of potato chips. In European factories, some computer vision systems are used for the on-line evaluation of potato chips, allowing chips to be sorted according to defects such as black spots or blisters. Some researchers have been also working on a promising...

Transition state theory was used to study enthalpy-entropy compensation for water loss during air drying of potato and apple slices. Slices of either potato or apple of 4-mm thickness, 40 mm diameter and air drying temperatures of 323, 333, 343, and 353 K were employed in the experiments. Moisture content and internal potato and apple slice tempera...

By applying the transition state theory, enthalpy–entropy compensation was studied for water loss data obtained during deep-fat frying of three kinds of potato chips: control, blanched and dried. Two alternative approaches were used to obtain the isokinetic temperature: enthalpy/entropy relationship and rate factor/activation energy relationship. V...

Acrylamide formation in French fries was investigated in relation to blanching and asparaginase soaking treatments before final frying. Par-fried potatoes of Bintje variety were prepared by cutting strips (0.8×0.8×5cm) which were blanched at 75°C for 10min. Unblanched strips were used as the control. Control or blanched strips were then dried at 85...

The objective of this research was to study the kinetics of oil absorption and distribution in the structure of potato slices during frying, considering the effects of three oil temperatures and a blanching pre-treatment. Either raw or blanched potato slices (Desirée variety, diameter: 30 mm, thickness: 3.0 mm) were fried at three constant (±1 °C)...

Acrylamide diminishing in potato slices and strips was studied in relation to frying temperature and some pre-treatments. Potato slices (Tivoli variety, diameter: 37 mm, width: 2.2 mm) were fried at 150, 170 and 190°C until reaching moisture contents of ∼1.8 percent. Prior to frying, potato slices were treated in one of the following ways: (i) blan...