Marit Risberg Ellekjær

Instrumental and sensory analysis of fresh Norwegian and imported apples

Abstract Sensory profiling, instrumental texture measurements and volatile composition was used to characterise ten Norwegian and three imported apple varieties. Principal component analysis of sensory data identified an odour/flavour-factor and a texture factor along the first and second principal component, respectively. The main volatile components separating the apples were propyl acetate, butyl acetate, 2-methylbutyl acetate, hexyl acetate, ethyl acetate, ethyl butanoate, 1-butanol, ethanol and α-farnesene. The first four mentioned volatiles were related to fruity and sweet sensory attributes, while the latter were related to sour, bitter and grassy attributes. Sensory hardness, chewiness and mushiness correlated well with instrumentally measured force and work required for penetration of the flesh. Sensory odour- and flavour attributes showed varying correlations by principal least squares regression to volatile composition and texture-data separately. Sour, sweet and grassy flavours were best explained when sensory odour- and flavour-attributes were correlated to texture-measurements and volatile composition-data at the same time.

A case study of the use of experimental design and multivariate analysis in product improvement

Abstract The overall purpose of this study is to identify an effective strategy for improving the sensory quality of a product. A study on processed cheese was used to develop and illustrate our ideas. A screening experiment, with seven processing and ingredient variables, was performed in order to identify variables with the greatest effect on the sensory quality. A fractional factorial design with resolution IV was used to keep the number of experimental runs to a minimum. ANOVA and normal plots were used to evaluate the effects of the different factors on the sensory variables one by one. The same factors were identified as being important when the scores from a principal components analysis (PCA) of the sensory variables were analysed. PCA was found to be of value in identifying samples that had improved properties compared to todays product in addition to having a low intensity of undesirable properties.

Low-fat mayonnaise: influences of fat content, aroma compounds and thickeners

The effects of fat content and thickeners, propylene glycol alginate (PGA; 1.40%) and guar gum (1.55%), on sensory and instrumental quality descriptors on reduced fat mayonnaises (15 and 30% fat) w ...

Determination of the sodium chloride content of sausages by near infrared spectroscopy

Near infrared (NIR) reflectance and transmittance spectroscopy were studied as potential methods for determination of the sodium chloride (NaCl) content of sausages. Fifty-seven batches of sausages with varying chemical composition were produced. The NaCl content of the sausages varied between 1.4 and 2.2%. NIR reflectance and transmittance analyses were performed on both the sausage-mixes and the sausages. Comparable accuracy was achieved when performing the NIR analysis of either the sausage-mixes or the sausages. The NIR reflectance and transmittance methods were able to determine the NaCl content of the sausages with prediction errors of 0.04% and 0.07%, respectively. This suggests that both methods could be utilised for prediction of the NaCl content, in addition to the main chemical components of the sausages.

The use of experimental design in the development of new products

Experimental design methods are tools for conducting informative, time‐ and cost‐effective experiments. Used during product development, these methods can contribute to building quality into products as well as shortening the development cycle time. These techniques make it possible to study the effect of many factors (parameters) simultaneously, to select the factor combination that results in both improved quality and reduced cost, and hence allow for the development of reliable and robust products of high quality. In addition, these methods provide a systematic approach for problem solving during the product development process. This article provides a non‐technical discussion of the role of experimentation and the advantage of using experimental design during product development. Different experimental design methods and examples of their application during product development will also be presented.

Meat speciation by near infrared reflectance spectroscopy on dry extract

Professionals and consumers want to control the origin of meat, while producers can profit by mixing minced meat from low cost species into high value meat. Near infrared (NIR) spectroscopy on dry extracts was studied as a method for speciation of minced beef, pork, mutton and mechanically recovered poultry meat. This was divided into three levels: (1) classifying into “labelled species or not?”, (2) into one of four possible species or (3) predicting the degree of substitution of minced beef with other species in a model study. Minced meat from 68 carcasses from four animal species ranging from low to high fat contents were centrifuged. Extracted meat juices (0.5 mL) were dried on glass microfibre filters and the reflectance measured. Using the range 780–2500 nm and different methods of discriminant analysis by cross-validation, the 68 samples were classified 90–100% correctly according to speciation at levels 1) and 2). Level 3) included a Simplex design model study using 350 mixtures of the 68 centrifuged juices. Predicting the relative amounts from each species in samples containing 50–100% beef juice gave cross-validated prediction errors of 12% (w/w) for beef, 8% for pork and 7% for mutton and poultry. The results showed that NIR on dry extract might be used as a rapid screening method for classification and optimised to detect species adulteration.

Using raw material measurements in robust process optimization

Abstract Unwanted variation due to variable raw material quality is often a problem in production processes. Robust process optimization seeks to reduce the effects of such variation by identifying settings of the adjustable factors that makes the process less sensitive to the variations. This paper develops a unified framework for studying and developing robust process optimization and process control techniques. We divide the factors of the process into groups based on characterizations of their properties. We also develop a robust process optimization technique for batch-wise processes, called batch-wise robust process optimization, which utilizes all available measurements of raw material qualities at the start of each production batch. The technique achieves a reduction of variability due to variation in raw material qualities, compared to ordinary robust process optimization. Two examples taken from baking of hearth bread illustrate the technique.

Effect of Dough Processing Conditions and DATEM on Norwegian Hearth Bread Prepared from Frozen Dough

ABSTRACT The objective of this study was to examine treatments that directly influence Norwegian lean doughs destined to be frozen. Therefore a strip-block experimental design with four dough treatment factors (wheat flour blend, diacetyl tartaric acid esters of monoglycerides [DATEM], water absorption, and dough temperature) and two storage factors (frozen storage time and thawing time) was used. Four levels were selected for frozen storage time and two levels were selected for the remaining factors. After frozen storage (2–70 days), the doughs were thawed and baked. Principal component analysis showed that to obtain a high loaf volume and bread score after freezing, a high dough temperature after mixing (27°C) was essential. The highest form ratio (height/width) level was obtained after 28 days of frozen storage and with a short thawing time (6 hr). Analysis of variance (ANOVA) of dough treatments showed that an increase in dough temperature from 20 to 27°C after mixing resulted in a significant increas...

Detecting non-bovine meat in beef patties by dry extract spectroscopy by infrared reflection—a preliminary model study

Meat producers can profit by mixing meat from low cost species into more expensive meat, e.g. beef, without stating this on the product label. Consumers want to know the origin of the meat they eat, e.g. to avoid meat from certain animal species. Consequently, a fast and reliable method to identify the animal species in meat mixtures is needed. The technique Dry Extract Spectroscopy by Infrared Reflection (DESIR), modified from Dr. M. Meurens, was used in this model study, as a method to measure the amounts of lamb, mechanically recovered poultry, and/or pork mixed into ground bovine meat.

Sensory quality of low-fat sausages affected by fat substitutes☆

Abstract Fat substitutes have been introduced to low-fat meat products to make the texture more acceptable. This study focuses on the effect of the polysaccharides iota-carrageenan, xanthan and guar gum on the sensory quality of low-fat sausages. Low-fat sausages with these three fat-substitutes and sausages with regular fat content were analyzed by conventional sensory profiling. The data were analyzed by principal component analysis. The low-fat sausages with iota-carrageenan were most similar to the ordinary sausages. Low-fat sausages with guar gum and xanthan were similar to each other. Off-odours were perceived in the sausages with guar gum and xanthan, and these sausages were also less firm and less elastic than ordinary sausages and sausages with iota-carrageenan.