Mashing of rice with barley malt under non-conventional process conditions for use in food processes

Non-conventional mashing conditions are relevant in the development of a lactic acid-fermented soymilk beverage where mashed rice is the source of carbohydrates for the fermentation and sweetness of the beverage. Advantages in the process layout could be achieved by mashing at higher pH and lower malt concentrations than normally used in the brewing industry. the work reported here assessed the consequences of mashing under non-conventional conditions. Malt concentration in the cereal part was varied from 25% to 70% (w/w), pH was varied within 5.3 to 7.1, and prolongation of the holding times at 50°C and 62°C was investigated. Regression equations have been established for predicting yields of soluble protein, low molecular weight sugars and total fermentability as functions of pH and malt concentration. the results showed that the maltose yield was constant while glucose, maltotriose and total fermentable sugar yields decreased slightly with increasing pH and decreasing malt concentration. Prolonged mash holding times at 50°C and 62°C gave minor increases in protein yields only. It is concluded that it is quite acceptable to use non-conventional mashing conditions when a mashing step is integrated in other food processes.     

Atlantic Salmon Average Fat Content Estimated by Near-Infrared Transmittance Spectroscopy

Near-infrared transmittance spectroscopy was used to determine the average fat content in farmed Atlantic salmon fillets with skin and scales. The fat content was 5.7–17.6% and weight range 1.0–5.4 kg. A partial least square regression including 43 salmon resulted in a multivariate prediction correlation of 0.97 and a root mean square error of cross validation of 0.75%. Regression models using 6 to 9 wavelengths in the 850–1048 nm range gave somewhat lower prediction errors than a model using 100 wavelengths. Results showed that NIR transmittance was suited to determine fat content nondestructively in whole salmon fillets with skin and scales.     

Review Article. Directional ocean wave spectra as observed with multifrequency continuous wave radar

A multifrequency continuous wave radar has been developed. By means of this, the directional spectra of ocean irregularities (waves and turbulence) can be measured by illuminating the sea surface simultaneously over a frequency band of some 30 MHz in the 6 GHz region, using 15 frequency spacings. By measuring amplitude and phase, the power spectrum (Doppler spectrum) associated with each of the 15 discrete sea surface irregularity scales is obtained, as is, independently, information about velocity. From the Doppler spectra associated with each of the 15 irregularity scales investigated (6-150 m) it is possible to distinguish between the contribution from the coherent gravity waves and the incoherent random irregularities. Experimental results from a set of different geophysical situations are given with reference to a general theoretical presentation.     

EFFECT OF OTHER HYDROCOLLOIDS ON THE TEXTURE OF KAPPA CARRAGEENAN GELS1

The effect of different hydrocolloids on the breaking strength, cohesiveness and rigidity of kappa carrageenan gels was studied using comression tests with the Instron. Instrumental measurements were supplemented with benchtop sensory evaluation of texture by mouth, gel clarity and syneresis. The evaluated hydrocolloids included locust bean gum, iota carrageenan, amidated low methoxyl pectin, xanthan gum, and their selected combinations. Best gels were obtained by using 0.15% kappa carrageenan and 0.85% iota carrageenan, or 0.2% kappa carrageenan, 0.2% locust bean gum and 0.6% amidated LM pectin. Although none duplicated the textural quality of gelatine gels, they represented a wide range of interesting and potentially useful textures.     

OXIDATION MECHANISMS IN REAL FOOD EMULSIONS: METHOD FOR SEPARATION OF MAYONNAISE BY ULTRACENTRIFUGATION

With the aim of studying partition coefficients of antioxidants and secondary oxidation products in a real food emulsion a method for the separation of mayonnaise was developed. The method included freezing and a mild precentrifugation step followed by ultracentrifugation at 197,500 x g. The precentrifugation separated most of the oil (96%) from the rest of the mayonnaise. The ultracentrifugation separated the remaining fraction into four phases: a small oil phase constituting 0.25% of the total, a relatively small emulsion phase (approximately 5%, w/w), an almost translucent aqueous phase that constituted the largest fraction (88%, w/w), and lastly a precipitate (6%, w/w). The objective of the present investigation was to test the efficiency of the method to separate a hydrophobic compound, the methyl ester of C23:0, and a hydrophilic compound, NaCl. The oil soluble compound (C23:0) was almost completely recovered (96%) in the oil phase after the preseparation step, whereas the water soluble compound (NaCl) was almost completely recovered (86%) in the aqueous phase obtained     

THE CONTINUOUS WOK — A NEW UNIT OPERATION IN INDUSTRIAL FOOD PROCESSES

The preparation of fine cut vegetables and meat by stir‐frying is characterized by a short cooking time and high rates of heat and mass transfer, which makes scale‐up difficult. A new principle for carrying out an industrial, continuous stir‐frying process is studied at pilot plant scale. The ingredients are transported in a horizontal, open frying tube by a conveyor helix while being tossed by scrapers and stirring rods mounted on the helix. During the frying process the average product temperature stabilizes around 80C, despite the intense heating, and this may explain why the texture of stir‐fried vegetables is firmer than the texture of vegetables cooked in water. However, the heat inactivation of a model microorganism applied as a surface contaminant showed that the effective surface temperature was above 90C which ensures a safe process. Vigorous evaporation from the free surfaces of the turning pieces may cause this temperature gradient to be established by an evaporation cooling effect.     

Extended shelf life milk—advances in technology

This paper describes trends and technological advances in the dairy industry for extended shelf life milk. Demands for longer shelf life and wider distribution of milk and milk products have resulted in the development of processes and packaging concepts to increase the shelf life of these products in cold chain distribution. Factors important for the shelf life of milk are described in detail, and changes necessary from normal pasteurized production are suggested. Various processing methods such as microfiltration, injection and infusion heat treatments are described, and advantages and disadvantages of the different methods explained. In addition, the contamination sources from process to package are discussed, and the prevention of such recontamination in the filling machine is proposed. The paper describes existing and novel methods for sterilization of packaging material in the filling machine and points to possible future developments in this important market segment in the dairy industry.     

LIPASE-CATALYZED PRODUCTION OF STRUCTURED LIPIDS VIA ACIDOLYSIS OF FISH OIL WITH CAPRYLIC ACID

Structured lipids containing eicosapentaenoic and docosahexaenoic acids were manufactured in a batch reactor by lipase-catalyzed acidolysis of fish oil with caprylic acid. The following free lipases (Lipase AP, Aspergillus niger ; Lipase P, Pseudomonus sp. ; Lipase AY, Candida rugosa ; Lipase AK, Pseudomonas fluoresescens ; Lipase F, Rhizopus oryzae ; Lipase D, Rhizopus delemar ) were screened under selected reaction conditions. The conditions were enzyme load 5%, substrate mole ratio 1:6 (fish oil: caprylic acid), and reaction temperature of 50C. Lipase AK had the highest activity and was suitable for production of structured lipids from fish oil. The optimal mole substrate ratio of fish oil to caprylic acid for Lipase AK was 1:6 to 1:8. The time course of the reaction at different enzyme loads demonstrated that 40% incorporation of caprylic acid could be obtained for Lipase AK in 5 h with 10% enzyme load. Addition of water had little effect on the activity of the lipase. Lipase AK and Lipozyme IM were further compared under the same conditions, in which Lipase AK had a slightly higher incorporation of caprylic acid, similar acyl migration of caprylic acid from sn-1,3 positions to the sn-2 position, and a slightly lower selectivity towards docosahexaenoic acid.     

Non-Destructive Determination of Fat and Moisture in Whole Atlantic Salmon by Near-Infrared Diffuse Spectroscopy

A near-infrared spectrometer equipped with an interactance optical fiber probe was used to determine the average crude fat and moisture content in the muscle of whole Atlantic salmon (Salmo salar). The fat contents were 8.8—19.2% and moisture 61.0—70.8%, and fish weight range 1.0—5.7 kg. A partial least square regression including 49 salmon resulted in root mean square error of cross validation of 1.12% fat (R = 0.87) and 0.98% moisture (R = 0.86). Results showed that NIR interactance was a suitable non-destructive screening method for fat and moisture content in farmed Atlantic salmon.     

SPECTRAL-DOMAIN MODELLING OF SUPERCONDUCTING MICROSTRIP STRUCTURES

We present an analysis of thin microstrip superconducting structures in which the effects of the superconducting material, of finite complex conductivity and finite thickness, are taken into account through the concept of sheet impedance coupled with an extension of the Spectral Domain Immittance Approach. The effect of the magnetic field on the penetration depth in the superconductor is included by solving the Ginzburg–Landau equations within the thin-film approximation (t/λ₀ ≪ 1). The state of the material is determined self-consistently in such a way that when the critical field is exceeded, the material systematically shifts from the superconducting to the normal state. Special attention is paid to the behaviour of the system in the neighbourhood of the critical temperature, T/T_c ≃ 1. We report that, in some cases, the propagation constant of a superconducting microstrip line attains a maximum when the real and imaginary parts of the conductivity are approximately equal. Numerical results for a microstrip line and a patch resonator are presented and compared with available data to document the validity of the approach. © 1997 John Wiley & Sons, Ltd.