Herstellung und Anwendung von Zuckerkulör aus Stärkeprodukten

Production and Application of Caramel Colour from Starch Products. Caramel colours are very dark brown to black syrup-like liquids or powdered products which are used for colouring foods. They are obtained by special processes by controlled heat treatment of commercially available sugars. To promote caramelization permitted technical adjuvents may be employed. Due to their functional properties they are suitably classified into 4 classes: For the production mainly starch degradation products like starch sugar or glucose syrup are used as raw material. In the Federal Republik of Germany the production rate and the consumption run up to about 10000 t/annum.     

Beziehung zwischen Sorte und Umweltbedingungen zum Trockensubstanz- und Stärkegehalt von Kartoffeln

Relationship of Sort and Environmental Conditions with Dry Substance and Starch Content of Potatoes. The effect of different factors (sort, site, etc.) on dry substance and starch content, resp, of potatoes was studied. In detail, the parts of factors on variability of dry substance and starch content were: Furthermore, from the results arises that the climate can exert a larger effect on variability of starch content on the investigated site.     

Sterilisation with 60cobalt γ-radiation of immobilised enzyme membranes for use in electrodes for food analysis

Enzymes can be conveniently immobilised on modified nylon-6,6 mesh ( I ) produced by successive treatments of nylon-6,6 with dimethylsulphate, lysine spacer and glutaraldehyde:      

Tepary Bean Starch. Part I. Physico-chemical Properties

Starch of high purity was isolated by a simple procedure from tepary beans (Phaseolus acutifolius var. latifolius). Granules were spherical to oval with a birefringence pattern similar to that of other legume starches. Under SEM they appeared smooth with no evidence of fissures. They showed a normal distribution of diameters with a range of 15.5–59.8 μ and a mean of 33.5 μ. Tepary starch had an amylose content of 30.7% and a gelatinization temperature range of 70.5–84.0°C. Other properties were also determined. Fractionation provided an amylose fraction with a β-amyloysis limit of 76.3% and an average DPη of 618. The amylopectin fraction had an average values of 33, 22 and 10 glucose units respectively.     

Cover Image,Volume 97, Issue 6

The cover image, by Sibel Ya?c?, is based on the Research Article Effects of instant controlled pressure drop process on physical and sensory properties of puffed wheat snack , DOI: 10.1002/jsfa.7973 .

     

Effect of root zone pH and form and concentration of nitrogen on accumulation of quality‐related components in green tea

Green tea quality is greatly influenced by concentrations of free amino acids, polyphenols (mainly catechins) and caffeine. The present study investigated the principal relationship between selected nutritional factors (form and concentration of N supply, root zone pH) and accumulation of these quality‐related components of tea (Camellia sinensis (L.)) plants. Tea plants were hydroponically cultured with NH , NO and NH NO at pH 4.0, 5.0 and 6.0 in one experiment and supplied with varying N concentrations (0.75, 2.0 and 4.5 mmol L^?1, NH /NO^?₃ = 3:1) in another experiment. Concentrations of free amino acids were considerably higher in NH ‐ than in NO ‐fed plants. This was attributed to the much greater absorption of NH compared with NO . Furthermore, the relative allocation of absorbed N to free amino acids, particularly theanine and glutamine, was substantially increased by NH nutrition, suggesting that NH was more readily assimilated than NO into theanine. The concentration of caffeine was increased in NH ‐ and (NH NO )‐supplied plants, whereas concentrations of catechins were reduced in (NH NO )‐fed plants. Root zone pH did not influence concentrations of most free amino acids in young shoots, with the exception of theanine, which increased at low pH (4.0) irrespective of N form; this likely stemmed from an accumulation effect, as growth decreased more strongly than N absorption. Raising the N supply increased plant N allocation to free amino acids. The increase was most striking for arginine, while theanine was only marginally affected. This may have adverse consequences for green tea quality, as less favourable taste characteristics have been attributed to arginine. Copyright © 2007 Society of Chemical Industry     

Ultrasonic estimation of solid/liquid ratios in fats,oils and adipose tissue

Data are presented for the speed of transmission of pulses of 2.5 MHz ultrasound through fats and oils at temperatures in the range ?50 to +110°C. It is suggested that a measurement of the speed of ultrasound (V), which is greater in solid fats (V_s) than in oils (V_L), might be used to provide an estimate of the proportion of solid in a partially solidified fat. An acoustic parameter ? is defined such that: and it is suggested that ? might be used as a practical index for determination of the volume fraction of solid fat. This procedure might be useful under conditions unsuited to the established methods of dilatometry, calorimetry or nuclear magnetic resonance. As an example of a possible application, measurements are presented for the speed of ultrasound in pig adipose tissues selected to show a range of consistencies which, by subjective assessment and by penetrometer measurements, ranged from ‘soft’, and therefore unsuited for the manufacture of bacon, to ‘hard’. After allowing for the contribution of the fat-free tissue, it was estimated that the lipid in the tissues ranged from about 20 to 88% (by volume) solid. The variation in ? explained 88% of the variance in the penetrometer measurements.     

Perspectives on the history of research on starch

Starch has been used over several millennia for a number of different applications. However, research on understanding this substance only spans about three centuries starting with Leeuwenhoek who observed it in 1716. This story of discovery of the molecular structure and architectural makeup of starch is chronicled in a series of six essays of which this is the third with a focus on contemporary terminologies used in the 19th and early 20th centuries and its impact on advances in starch. Following the discovery of diastase, researchers focused on understanding the action of diastase on “transforming” starch into sugar. Besides maltose, they found that the products consisted of a range of dextrins with different abilities to complex with iodine. However, the nomenclature of the products that were obtained under a myriad of experimental conditions gave rise to confusions and misinterpretations, which transpired for over 30 years. Researchers also attempted to understand starch structure through systematic analyses of the different stages of starch breakdown. A new era of confusion in both nomenclature and structural interpretation started in the early 20th century with the discovery of cyclodextrins that were obtained from starch using the microorganism B. macerans. This gave rise to the school of “the low molecular elementary unit hypothesis” for starch structure, which lasted for about 25 years.

     

Estimation of the biological value of food proteins by a modified equation of the essential amino acid index and the chemical score

A modified essential amino acid index equation incorporating a digestibility factor (MEAAI), and a chemical score index (CSI) were developed from the essential amino acid profile of 18 different food proteins hydrolysed by the combined but sequential action of papain and pronase E enzyme systems. The essential amino acid composition of whole egg was used as a reference standard. The following equations were proposed. In which a is the value of the limiting amino acid in the sample, and a_e is the corresponding value in whole egg. Both equations were used to calculate the biological value of different protein foodstuffs. There was a close agreement between values obtained using the equations and reported values for the same foodstuffs published in the literature. There was also a close correlation (r = 0.665) between data obtained using MEAAI and those obtained using CSI in estimating biological values, suggesting that either equation could be used reliably and solely to estimate protein biological value of foods.     

Cover Image,Volume 98, Issue 9

The cover image, by Noorani Barkat et al., is based on the Research Article Effect of harvest time on the levels of phytochemicals, free radical‐scavenging activity, α‐amylase inhibition and bile acid‐binding capacity of spinach (Spinacia oleracea), DOI: 10.1002/jsfa.8862 .

     

Cover Image,Volume 98, Issue 11

The cover image, by Ciara Duffy et al., is based on the Research Article In vitro evaluation of chitosan copper chelate gels as a multimicronutrient feed additive for cattle, DOI: 10.1002/jsfa.8939 .

     

Cover Image,Volume 97, Issue 3

The cover image, by Borja Millán et al., is based on the Research Paper Image analysis‐based modelling for flower number estimation in grapevine, DOI: 10.1002/jsfa.7797 .

     

Perspectives on the history of research on starch Part IV: On the visualization of granule architecture

Starch has been used over several millennia for a number of different applications. However, research on understanding this substance only spans about three centuries starting with Leeuwenhoek who observed it in 1716. This story of discovery of the molecular structure and architectural makeup of starch is chronicled in a series of six essays of which this is the fourth with a focus on visualizing the granule, its development and architecture. Since the starch granule was visualized initially, researchers focused on the content and composition of the granule and also tried to understand what they saw by way of layers, polarization, and staining properties using a microscope. Two schools of thought prevailed in the 1800s with regards to granule development. Confusion prevailed with respect to terminologies and composition through this period. The first model of the crystallized granule was proposed in the late 19th century and it was not until mid‐20th century that the blocklet and crystalline arrangement of starch was understood. However, the crystallinity and helical complex between AM and iodine continued to obscure the source of starch crystallinity during the second half of the 20th century.

     

Cover Image,Volume 98, Issue 8

The cover image, by Rosario Sánchez‐Gómez et al., is based on the Research Article The Microvine, a plant model to study the effect of vine‐shoot extract on the accumulation of glycosylated aroma precursors in grapes, DOI: 10.1002/jsfa.8802 .

     

Cover Image,Volume 97, Issue 2

The cover image, by Shanise Lisie Mello El Halal et al., is based on the Research Paper Morphological, mechanical, barrier and properties of films based on acetylated starch and cellulose from barley, DOI: 10.1002/jsfa.7773 .

     

Cover Image,Volume 97, Issue 7

The cover image, by Haiyan Zhou et al, is based on the Research Article Mannanase Man23 mutant library construction based on a novel cell‐free protein expression system, DOI: 10.1002/jsfa.8029 .

     

The relative merits of the presence of hull on the nutritional qualities of the African yam bean flour

The flour from three colour cultivars of hulled and dehulled seeds of the African yam bean (AYB) (Sphenostylis stenocarpa) was analysed for anatomical fractions; proximate, mineral, fatty and amino acids composition. The seed hull varied between 8.25% and 9.14%. Na, K. Ca, Mn, Fe, Zn are preferably found in the hulled samples. Essential fatty acids as well as essential amino acids are more enriched in the hulled samples than in the endosperm. Correlation coefficient results showed that proximate composition (r, r, r), mineral composition (r, r, r), fatty acids (r, r, r), fatty acids saturation (r, r, r) and amino acids (r, r, r) were significant at α = 0.05 in the samples shown in parentheses with values having high positive correlation coefficients ranging from 0.82 to 1.00. These results showed that dehulling of African yam bean seeds will lead to reduction in the nutritional qualities of the AYB.     

Cover Image,Volume 98, Issue 14

The cover image, by Xiumin Zhang et al., is based on the Research Article Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production in in vitro ruminal culture, DOI: 10.1002/jsfa.9056 .

     

A novel enzymatic method for the measurement of lactose in lactose-free products

The cover image is based on the Research Article A novel enzymatic method for the measurement of lactose in lactose-free products by David Mangan et al., DOI: 10.1002/jsfa.9317 . This cover was supported by Megazyme.

     

Cover Image,Volume 97, Issue 12

The cover image, by Wai Chin Li and Chin Fung Chow, is based on the Review Adverse child health impacts resulting from food adulterations in the Greater China Region, DOI: 10.1002/jsfa.8405 .