Kernel‐based gluten contamination of gluten‐free oatmeal complicates gluten assessment as it causes binary‐like test outcomes

Gluten‐free (GF) foods, whose claim compliance is controlled at the ‘serving level’, hold better chances of protecting gluten‐intolerant consumers. This is particularly true for GF oatmeal, as oats are easily contaminated with gluten‐rich kernels of wheat, rye and barley, which remain intact to the spoon as pill‐like flakes. A single contaminant kernel in otherwise pure oats results in GF labelling noncompliance, thereby posing a risk to patients with coeliac disease. Our in‐market survey of 965 GF oatmeal servings uncovered that one in fifty‐seven servings exceeded the GF labelling maximum of 20 mg kg^?1 (i.e. 20 ppm). The noncompliance pattern was ‘binary‐like’, with kernel‐based contamination the suspected pass/fail driver. We have highlighted probabilities of misassessment for various sample sizes in light of oat's natural propensity for kernel‐based contamination and proposed use of attribute‐based sampling for compliance assessment, thereby providing a way to assess/manage/control ‘rates of servings containing a contaminant kernel’ within acceptable limits with high confidence.     

Influence of quinoa roasting on sensory and physicochemical properties of allergen‐free,gluten‐free cakes

The objectives of this study were to determine pasting properties of non‐roasted (NR) and roasted quinoa (RQ) and to investigate the effect of RQ on consumer acceptance and physicochemical properties of an allergen‐free, gluten‐free cake formulation. Quinoa seeds were roasted at 177 °C for 15 (R15), 30 (R30) and 45 min (R45), and flours were analysed for pasting properties. Five cakes including a commercial chocolate cake (CCC) and cakes made with NR and RQ flours were evaluated for preference by fifty panelists. Quality parameters included colour, water activity, moisture content, firmness, weight and height. Peak and final viscosity increased with roasting time. The NR cake had the highest sensory scores for appearance, colour and texture. On flavour and overall acceptability, CCC was the highest. Regarding quality data, CCC, NR and R15 cakes had similar L* values, while CCC had the lowest a*, b*, a_w, moisture content and firmness values.     

Effect of water,albumen and fat on the quality of gluten‐free bread containing amaranth

The aim of the research was the development of an alternative formula for gluten‐free bread (GFB) containing amaranth flour. GFBs were prepared using a 2³ factorial screening experimental design. The amount of water, albumen and fat varied in order to evaluate their impact on the textural, structural and sensory characteristics of the final product. Water amount had the greatest influence on bread characteristics. For a 33% water content increase (from 0.6 to 0.8 g g^?1 of flour) the firmness of the crumb decreased to 20% of the initial value. Also, for the same water content increase, the average pore size became 2.5‐fold greater. Albumen addition (from 0 to 0.04 g g^?1 of flour) influenced mainly crumb viscoelasticity (20% increase). Variations in fat amount did not significantly influence any of the response variables investigated. However, the combined addition of fat and albumen resulted in breads that received the best rankings in overall acceptance in sensory evaluation.     

Effect of butter content and baking condition on characteristics of the gluten‐free dough and bread

This study aimed to investigate effect of butter content (0–30 g/100 g flour) and baking conditions hot air baking (HA), microwave baking (MW) and hot air‐microwave baking (HA‐MW) on quality of the rice flour dough and bread. The increased butter (up to 15 g butter/100 g flour) enhanced elastic modulus (G′) and viscous modulus (G″) of dough and specific volume of bread. Additionally, the increased butter improved crust colour and reduced hardness of the bread. The HA‐MW and MW conditions were useful for the gluten‐free bread by reducing baking time and predicted glycemic index (GI), regardless of butter content. However, enthalpy of retrogradation and crystallinity in the HA‐MW and MW bread stored at 4 °C for 7 days were increased and higher than those of the HA bread, indicating a faster staling. The predicted GI of both MW and HA‐MW bread remained at a medium level during storage.     

Influence of kidney bean,field pea and amaranth protein isolates on the characteristics of starch‐based gluten‐free muffins

This study was undertaken to see the effect of kidney bean (KB), field pea (FP) and amaranth (AM) protein isolates on the viscoelasticity and gluten‐free muffin‐making properties of starch‐based batter. The characteristics of gluten‐free muffins were also compared to those prepared with wheat gluten (WG). The incorporation of different protein isolates enhanced batter viscoelasticity (increased storage and loss modulus and decreased tan δ) and resulted in muffins with higher specific volume, springiness and cohesiveness. Firmness of the muffins varied with the source of protein isolate. KB protein isolates resulted in firmer muffins compared to those made from FP, AM and WG. The crust colour became more reddish‐brown on incorporation of protein isolates, while crumb colour varied with the source of protein. Overall, the results revealed that KB, FP and AM protein isolates can be successfully used to prepare gluten‐free muffins with characteristics comparable to those made from wheat gluten.     

Effect of the shape of rice starch granules on flour characteristics and gluten‐free bread quality

The effect of three different rice varieties with different starch shapes (Seolgaeng (SG), round starch structure; Samkwang (SK), polygonal starch structure and Boramchan (BRC), polygonal starch structure) on rice flour characteristics and gluten‐free bread baking quality was investigated. Rice flours were produced by dry milling and passed through a 200 mesh sieve. Electron microscopy revealed that the structure of SG grains, with round starch granules, possessed larger void spaces than SK and BRC, composed of polygonal starch granules. For this reason, SG grain had low grain hardness and consequently, it was milled to a fine flour with low damaged starch content. The thermo‐mechanical properties were determined by Mixolab, which revealed that SG was gelatinised rapidly and maintained high viscosity after gelatinisation. These characteristics gave SG flour the ability to build up bread structure without gluten. Specific volume and crumb hardness of gluten‐free rice breads made of SG, SK and BRC flours were 3.37, 3.11 and 2.12 mL g^?1 and 2.61, 2.76 and 6.46 N, respectively. The SG flour with round starch structure is appropriate for making gluten‐free rice breads.     

Effect of the side chain size of 1‐alkyl‐pyrroles on antioxidant activity and ‘Laba’ garlic greening

Previous studies showed that 1‐alkyl‐pyrroles not only occur in fresh food products postulated as a natural antioxidant but also might be involved in garlic greening. In the present study, a series of 1‐alkyl‐pyrroles with different side chain size were synthesised to study the relationship of structure and antioxidative activity and their effects on ‘Laba’ garlic greening. The antioxidative activity of these compounds was evaluated by the method of scavenging ABTS˙ and DPPH˙. Results showed that increasing the size of R groups on the side chain, the antioxidative activity decreased gradually against the two radicals. The 1‐alkyl‐pyrroles generally exhibited stronger scavenging activities against ABTS˙ than DPPH˙. In contrast, their corresponding amino acids except for tyrosine showed almost no antioxidative activities while pyrrole exhibited much weaker activity as compared with the 1‐alkyl‐pyrroles, suggesting that the 1‐alkyl‐pyrroles donate H‐atom from pyrrole moiety rather than side chain to quench the two radicals. On the other hand, all 1‐alkyl‐pyrroles can turn newly harvested garlic green but to a different extent. All these results suggested that these pyrrole derivatives occurring in foodstuff played an important role in either protecting foodstuff from oxidation or acting on pigment precursors during ‘Laba’ garlic greening.     

Identification of aroma‐active compounds in fresh and stored ‘Mor’ mandarins

In this study, gas chromatography–olfactometry (GC‐O) (sniffing) combined with gas chromatography–mass spectrometry (GC‐MS) analysis was applied to identify volatile aroma‐active compounds in homogenised segments of fresh and stored ‘Mor’ mandarins. The GC‐O nasal impact frequency method was used to identify Twenty‐three aroma‐active compounds, of which seventeen odorants were identified by GC‐MS. The aroma of fresh ‘Mor’ mandarins derived from a mixture of eleven odorants that contribute ‘green’ [(E)‐3‐hexenol and hexanal], ‘fresh’ [(E)‐carveol], ‘fruity’ (ethyl 2‐methylbutanoate), ‘citrus’ (limonene), ‘floral’ (linalool), ‘musty’ (β‐myrecene and γ‐terpinene), ‘potato’ (α‐terpinene), ‘mushroom’ (unknown 2) and ‘cabbage’ (α‐cubebene) odours. During postharvest, storage losses were observed in ‘green’ [(E)‐3‐hexenol] and ‘fresh’ [(E)‐carveol] odours, accompanied by increases in ‘fruity’ (ethyl propanoate) and several unpleasant aromas, such as ‘alcohol’ (ethanol), ‘musty’ [α‐pinene, (E)‐2‐nonenal and 1‐terpinen‐4‐ol] and ‘fatty’ (octyl acetate and δ‐cadinene) odours, all of which possibly account for the observed decrease in sensory acceptability after harvest.     

Breakdown of the insecticide ‘Gardona’ on plants and in soils

The breakdown of the insecticide ‘Gardona’ (2-chloro-1-(2′, 4′, 5′,-trichlorophenyl)-vinyl dimethyl phosphate, previously known as SD 8447) has teen studied, on cabbages, apple foliage and fruit, and rice, and in soils, using radio-isotope techniques under laboratory conditions. There was some isomerisation of ‘Gardona’ to its α-isomer on foliage. the initial half-life of ‘Gardona’ was about 1 day on the leaves and 4–5 days in medium loam soil. on foliage and in soils breakdown occurred by hydrolysis of the P-O-C bond to give initially 2,4,5-trichlorophenacyl chloride and demethyl ‘Gardona’ followed by reactions of the former involving reduction of the ketone group and reductive dechlorination to form a number of eight-carbon compounds. On foliage and on apple fruit the major breakdown products are conjugates of 1-(2′,4′,5′-trichlorophenyl)ethan-1-ol with sugars other than β-D -glucose. The breakdown products are of low toxicity to rats and, apart from the o-isomer, none has insecticidal activity and none inhibits cholinesterase.     

Effect of Altitude on Fruit and Oil Quality Characteristics of ‘Mastoides’ Olives

Olive fruit of cv ‘Mastoides’ grown on two locations at altitudes of 100 and 800 m were harvested at three dates and used for determination of average weight, fruit oil and moisture contents and the following oil quality characteristics: titratable acidity, peroxide value, K_232,270 coefficients, total phenol, tocopherol and chlorophyll content as well as fatty acid and phenol composition. Towards maturation, fruit moisture content decreased but oil content increased. Titratable acidity of oil of both altitudes was low, with higher the oil obtained from fruits from 100 m. Oil peroxide value was higher in the oil of fruits from 800 m at all harvest times and it showed an increase towards maturation in both locations. Total phenol content was higher in oil from 100 m elevation and showed a gradual decrease towards maturation at both altitudes. The ratio unsaturated saturated fatty acids was higher in oil of fruits from 800 m at the first two harvest dates but did not differ significantly at the third harvest. Only α-tocopherol was found in the oil from both elevations. Some phenolic compounds were detected in the first harvest but disappeared with fruit maturation, while other compounds not detected in the first harvest appeared later. Elevation influenced not only the phenol content but also its composition.     

Influence of jambolan (Syzygium cumini) and xanthan gum incorporation on the physicochemical,antioxidant and sensory properties of gluten‐free eggless rice muffins

This study was undertaken to prepare antioxidant‐rich gluten‐free eggless muffins from rice flour blended with varying amounts of jambolan fruit pulp (JFP) and xanthan gum (XG). The batters were evaluated for fundamental rheology, while muffins were analysed for physicochemical (colour, volume, water activity, total phenolic and flavonoid content), texture and sensory properties. The incorporation of JFP and XG increased batter viscoelasticity (increased G′ and G″ while decreased tan δ). JFP incorporation increased greenness (lower a* value), cohesiveness, resilience, water activity (a_w), total phenolic content, total flavonoid content, DPPH and ABTS inhibition of the muffins. Further, XG improved muffin quality characteristics (appearance, specific volume and resilience)_. Sensory analyses revealed that JFP incorporation improved the consumer acceptability of the muffins.     

Incorporation of canola proteins extracted by electroactivated solutions in gluten‐free biscuit formulation of rice–buckwheat flour blend: assessment of quality characteristics and textural properties of the product

Canola proteins extracted by electroactivated solutions were incorporated to gluten‐free biscuits made from blend of rice and buckwheat flours. Physical and textural properties were significantly influenced by these proteins. Isolates and concentrates did not behave in a similar way. A significant increase in diameter was noted for all of the supplemented samples. An increase in thickness was observed for the samples added with protein concentrate, whereas the spread ratio decreased for all the samples compared to control. The hardness of biscuits decreased with the addition of the proteins as compared to the control. The changes in biscuit hardness or fracture strength were in line with the changes in dough hardness. Biscuits containing protein concentrate had lighter, more aerated texture as shown by scanning electron microscopy with lesser amounts of gelatinised starch, indicating improved gas‐holding capacity and more stabilised structure. Protein‐supplemented biscuits have lower moisture and water activity.     

Chemical and microstructural evaluation of ‘hard‐to‐cook’ phenomenon in legumes (pinto bean and small‐type lentil)

Some physicochemical and microstructural characteristics of hard‐to‐cook (HTC) and easy‐to‐cook (ETC) pinto beans and small‐type lentils were compared. The development of HTC seeds was monitored over 6 months for changes in physicochemical properties. Results indicated that hardness, extent of water absorption and solid loss of HTC legumes were, respectively, 21–97%, 7–72% and 62–236% higher than those of ETC legumes. In addition, darkening of HTC beans and lentils was significantly higher than those of ETC ones. Scanning electron microscope observations indicated deteriorations in cytoplasmic contents of cotyledon cells of hard seeds. Phytic acid and total phenolic contents were, respectively, decreased 36–61% and 43–61% during storage, whereas hardness of seeds was increased 3–6 times. The soaking of hard seeds in sodium solutions resulted in the improvement in legume texture.     

Application of the fast sensory method ‘Rate‐All‐That‐Apply’ in chocolate Quality Control compared with DHS‐GC‐MS

This paper studied the fast sensory Rate‐All‐That‐Apply (RATA) method as a contributor to existing quality control (QC) in chocolate production by comparing it with the outcome of dynamic headspace sampling combined with gas chromatography–mass spectrometry (DHS‐GC‐MS). Seven different chocolates were evaluated by a semi‐trained panel using RATA. RATA showed potential as a sensory evaluation tool which could be part of QC programmes in chocolate production as RATA was efficient to perform and captured important sensory deviations, herein addition of excess lecithin and prolonged roasting. However, product deviations caused by long conching were only detected by DHS‐GC‐MS. A more extreme conching process must occur before it can be perceived by humans. RATA and DHS‐GC‐MS should be used as complementary methods in detecting future important issues in chocolate production. DHS‐GC‐MS detects product deviation from chemical perspectives while sensory evaluation gives information on quality parameters from a perceivable perspective influencing consumer satisfaction.     

Modelling the consensus and differences between assessors inspecting the colour quality of apples by ‘tree‐based modelling’

This research investigated the consensus and differences between different quality inspectors assessing the colour quality classification of a two‐coloured apple variety (Malus domestica Borkh cultivar ‘Jonagold’). An image analysis system measured the colour characteristics objectively. These objective measures formed the basic reference to compare the grading behaviour. Different quality inspectors were asked to assess the colour quality of different sets of apples applying the commercial quality standards. Agreement and association measures of the intra‐inspector contingency tables indicated a moderate ability of the inspectors to reconstruct their own quality classification. If the intra‐agreement and intra‐association were lower than a threshold, the repeatability of the inspector's assessments was considered as too poor and his classification results were omitted from the model development that simulated the apple colour classification behaviour. The statistical method ‘tree‐based modelling’ was applied to connect the individual quality assignments with the objective apple colour measurements. These models indicated that the blush colour was more important than the blush area for the quality assessment.The individual grading decision models were compared by correspondence analysis. Four different grading archetypes were detected and simulated. The predictive power of the four archetypal models was much higher than the predictive power of a consensus model including all inspectors. These results underlined the fact that poorly defined commercial standards lead to different quality interpretation. © 2000 Society of Chemical Industry     

‘Best before period once opened’ for honey samples from oceanic climates on the basis of their acidity types

Stability of food is of particular interest, as we should know the period for which a given food maintains its original quality. Acidity is a very important parameter as regards honey quality control. In this study we analysed a possible ‘best before period once opened’, regarding the evolution of acidity in honey throughout 30 months in samples from regions with oceanic climates. The study was carried out at room temperature (between 15 and 25 °C) by analysing all samples in duplicate each 5 months. We also researched the possible influence of induced granulation on the acidity evolution of honey samples, observing that as the analysis of variance showed significant differences at P‐value <0.05, this process had a significant influence on free acid and total acidity. All samples fulfilled the European Regulations regarding free acid, because no honey sample showed a free acid value higher than the limit of 50 meq kg^?1. Nevertheless, all honey samples suffered a continuous decrease of pH from 20 months on (averages: from 4.1 ± 0.25 at 20 months to 4.0 ± 0.23 at 30 months), and a continuous increase of both free acid (averages: from 27.6 ± 6.22 meq kg^?1 at 20 months to 33.5 ± 6.44 meq kg^?1 at 30 months) and total acidity (averages: from 42.5 ± 7.60 meq kg^?1 at 20 months to 44.7 ± 7.60 meq kg^?1 at 30 months). On the basis of acidity types, 20 months should be considered the ‘best before period once opened’ for honey from regions with oceanic climates.     

Postharvest performance of fresh‐cut ‘Big Top’ nectarine as affected by dipping in chemical preservatives and packaging in modified atmosphere

Fresh‐cut ‘Big Top’ nectarines were dipped in 2% (w/v) ascorbic acid–1% (w/v) calcium lactate and stored at 4 °C for up to 12 days in 10 kPa O₂‐ and 10 kPa CO₂‐modified atmosphere packaging (MAP). The used microperforated plastic film allowed O₂ and CO₂ concentrations to reach steady values from the fifth day in storage onwards. Samples stored in MAP after chemical dipping showed the highest visual quality score, slight browning symptoms, increment in firmness and very low ethanol and acetaldehyde content. The chemical dipping also increased antioxidant capacity, probably due to the effect of ascorbic acid. The results suggested that the control of yeasts was mainly exerted by MAP, whereas only a slight effect was achieved by the chemical dipping. Therefore, MAP plus ascorbic acid/calcium lactate dipping was the best combination to preserve phytochemical content, antioxidant capacity and microbiological safety of fresh‐cut nectarines during storage.     

Abscisic Acid in the Response of ‘Fortune’ Mandarins to Chilling. Effect of Maturity and High-Temperature Conditioning

The possible role of abscisic acid (ABA) and peel colour in chilling tolerance of ‘Fortune’ mandarins has been examined. Fruit stored at 2·5°C, but not at 12°C, showed pitting damage. The degree of damage changed considerably during development and maturity from November until May. Green fruit were more tolerant to chilling injury (CI). After colour break, chilling susceptibility increased from the beginning of December until January and February (the coolest season during the growing period) and declined towards May. This trend did not parallel changes in fruit colour index or free and bound ABA levels, which increased from November until May. At the time of chloroplast transformation to chromoplast a noticeable shift in free but not in bound ABA occurred. During storage, free ABA levels increased in fruits stored at 12°C, but not at 2·5°C. Changes in ABA with storage temperature depended on the stage of maturity of the fruits, but not on their susceptibility to CI. It has also been shown that there was no relationship between ABA content following exposure to 37°C and chilling tolerance. At all stages of maturity, the susceptibility of the fruits to CI and the free ABA levels of the flavedo decreased after conditioning the fruits for 3 days at 37°C. After storage at 2·5°C, the ABA levels of the conditioned fruit were similar or even lower than those of non-conditioned fruit. Treatment of fruit for 3 days with 10 μl litre^-1 ethylene increased free ABA about four times, whereas bound ABA remained nearly constant. This treatment enhanced cold-induced peel damage after prolonged storage. Thus, the ethylene-induced changes in free ABA appear not to be related to the induced changes in chilling susceptibility. The results obtained indicated, therefore, that free and bound ABA appear not to be involved on the adaptative mechanism developed in ‘Fortune’ mandarins to cope with chilling stress. © 1997 SCI.