Role of fat on the quality and shelf-life of gluten-free bread baked by Ohmic heating and conventional deck oven

The addition of fat to gluten-free (GF) bread can influence several quality attributes, such as texture and starch retrogradation. Therefore, the aim of this study was to investigate the influence of different fats on GF bread properties using two different baking methods (conventional and ohmic heating), in order to understand how these affect the physical bread quality, the formation of amylose-lipid complexes and its effect on crumb firming behavior. Fats (coconut, rapeseed, butter, and palm) with different physico-chemical properties, and physical state (solid, liquid) were tested in standard GF bread formulations. Results showed that fat significantly improved crumb pore uniformity. Crumb texture and pasting properties were mostly influenced by the type of fat, storage time and baking method. Staling was delayed in all breads added with fat due to the formation of amylose-lipid complexes, which were highest with palm fat and were usually higher when baked by ohmic heating.     

Feeding a concentrate rich in rapeseed oil improves fatty acid composition and flavor in Norwegian goat milk

Impaired quality due to a high content of free fatty acids (FFA) and off-flavors has caused challenges in the development of Norwegian goat milk products. The present study aimed to examine the effect of lipid-supplemented concentrates on milk fat content, fatty acid composition, FFA, lipoprotein lipase activity, sensory properties, and size of milk fat globules of goat milk. Thirty goats assigned to 3 experimental groups were fed different concentrates from 60 d in milk (DIM) until late lactation (230 DIM). The diets were (1) control concentrate (no added fat); (2) control concentrate with 8% (added on air-dry basis) hydrogenated palm oil enriched with palmitic acid (POFA); and (3) control concentrate with 8% (added on air-dry basis) rapeseed oil (RSO). The POFA group produced milk with the highest fat content, and fat content was positively correlated with the mean size of milk fat globules. Goats in the RSO group had a higher content of long-chain and unsaturated fatty acids, whereas milk from goats in the POFA group had a higher content of palmitic and palmitoleic acids (C16:0 and C16:1 cis). The control group produced milk with a higher content of short-, medium-, odd-, and branched-chain fatty acids compared with the 2 other groups. The content of FFA in milk was low in early and late lactation and peaked in mid lactation (90 DIM). A high content of FFA was correlated with poor sensory properties (tart/rancid flavor). The RSO group produced milk with lower content of FFA and off-flavors in mid lactation and a higher proportion of unsaturated fatty acids. Therefore, replacement of palm oil with rapeseed oil as a lipid source in dairy goat feed would be favorable.     

Can a structured emulsion (fat in water-fibre system) substitute saturated fat in cookies without hampering their quality?

Replacing fat and saturated fat in baked goods without affecting their quality characteristics is a challenging task. This study evaluated complete and partial substitution of saturated fats (butter and palm oil) by structured emulsions [SE, oil (sunflower) – in – water (fibre-water) emulsion] in cookies by investigating its impact on product quality. Nutritional labelling underlined a drastic reduction in saturated fatty acids [−35% (50% substitution) and −73% (100% substitution)] compared to their conventional counterparts (butter and palm oil). Partial substitution did not markedly affect physicochemical properties, while complete substitution resulted in thinner, harder and darker cookies compared to the controls. Particularly, cookies made with (50:50) structured emulsion – palm oil had the highest sensory scores, and they were perceived as soft, buttery and crunchy. Thus, the use of structured emulsion might be a valuable alternative to develop a potentially healthier product with acceptable sensory properties.     

Applications of chia (Salvia hispanica L.) in food products

BackgroundThe outstanding nutritional and technological properties lead to innovative applications of chia (Salvia hispanica L.) in food products.Scope and approachThe aim of this contribution is to give an overview of the various food application approaches for chia. The nutritional and technological properties of chia as well as its technological and innovative utilization are presented. Examples for the various applications in food products are given in five main topics: baked goods, dairy products, meat and fish products, gluten-free products and other products such as functional food, hydrocolloid and thickener.Key findings and conclusionsBesides the nutritional benefits of chia incorporation in food products the technological effects are emphasized very often. Summarized in five main topics, most authors conclude that chia is a valuable food ingredient for functional food development. The application of chia in baked goods for example is beneficial not only to improve the nutritional value but acting as hydrocolloid or substitute egg, fat or gluten. The increase of oil stability and applications as food thickener in novel food applications are of high importance too. As different chia fractions give various options for applications the utilization of chia for further food products will increase significantly in the future.     

小烛树蜡油脂凝胶的性质及作用机理研究

本文主要以小烛树蜡为凝胶剂,制备低芥酸菜籽油油脂凝胶。研究小烛树蜡添加量对油凝胶的相变、持油性、固体脂肪含量（solid fat content, SFC）、凝胶晶型及硬度的影响。实验结果表明,小烛树蜡添加量≥4%时,掺入低芥酸菜籽油中可制得具有固体性质的油凝胶,添加量为8%时,小烛树蜡使得持油能力（oil binding capacity, OBC）最强;SFC均在2%～6%之间,随着温度的升高,SFC减小;晶型分析表明小烛树蜡低芥酸菜籽油油凝胶主要晶型均在4.70 ?和3.80 ?附近;油凝胶硬度随着小烛树蜡添加量增大而逐渐增大,添加量为10%时小烛树蜡油凝胶硬度适中。为日后小烛树蜡油脂凝胶替代传统起酥油,生产具有高含量不饱和脂肪酸的烘焙食品提供理论基础。     

猪油和单甘酯含量对菜籽油凝胶油性质的影响研究

考察了将猪油与菜籽油按一定比例混合,并以单甘酯为凝胶剂形成的混合凝胶油的性质,探讨猪油和菜籽油质量比及单甘酯含量对混合凝胶油性质的影响,以制备出低饱和脂肪酸、能够更好地部分替代猪油的菜籽油混合凝胶油。测定了混合凝胶油的流变性质、质构性质、固体脂肪含量以及热力学性质。结果表明,当猪油和菜籽油质量比为5∶5,加入8%的单甘酯时,混合凝胶油与菜籽油凝胶油相比凝胶性质更好,在常温下固体脂肪含量更接近猪油。     

利用蜂蜡-米糠蜡制备大豆油凝胶油

利用蜂蜡、米糠蜡及其混合物作为凝胶剂,开发大豆油基凝胶油,并将制备的凝胶油与起酥油的物理性质进行比较。通过对2 种添加量下（5%、8%）蜂蜡和米糠蜡（蜂蜡与米糠蜡质量比10∶0、9∶1、8∶2、7∶3、6∶4、5∶5、3∶7、1∶9、0∶10）制备凝胶油的性质测定,结果发现随着米糠蜡比例的增加,凝胶油的硬度（11.9～140.4 g）呈先增加后减小再略有增加的趋势,当蜂蜡与米糠蜡比例为8∶2时,凝胶油的硬度最大,表明蜂蜡和米糠蜡混合后有协同作用;同时析油率采用离心的方法评价,结果发现米糠蜡比例较低（蜂蜡∶米糠蜡＞5∶5）时,凝胶油稳定,析油率为0%,且添加量8%条件下凝胶油的析油率低于普通起酥油。同时固体脂肪曲线、差示扫描量热法结果显示,在10～40 ℃条件下凝胶油的固体脂肪质量分数（8.5%～4%）显著低于起酥油（65%～20%）;融化峰值温度（50.2 ℃）高于起酥油（43.1 ℃）;X射线衍射结果显示8%蜂蜡-米糠蜡（8∶2）凝胶油样品的晶体形态（β’）与起酥油接近,都是细小的结晶。应用发现,蜂蜡与米糠蜡比例为8∶2,添加比例为8%的凝胶油具有较好的烘焙效果,使最终产品的固体脂肪含量大大降低,或许能为消费者拥有更健康的产品提供一条可行途径。     

Influence of SFC, microstructure and polymorphism on texture (hardness) of binary blends of fats involved in the preparation of industrial shortenings

Several binary blends of vegetable oils commonly used in industrial shortenings (i.e., palm oil (PO), hydrogenated palm oil (HPO), soybean oil (SO), hydrogenated soybean oil (HSO), low-erucic acid rapeseed oil (LERO), hydrogenated low-erucic acid rapeseed oil (HLERO)) were studied for their physical properties such as solid fat content (SFC) by nuclear magnetic resonance (NMR) and textural properties (hardness). Microstructure was also observed by microscopy in order to explain the variability in hardness for samples having the same SFC values. The blends studied by microscopy were the following: HSO, HPO and HLERO diluted in LERO. For these three blends which had the same SFC, the level of network structure was different. HSO diluted in LERO had more crystals, closer to each other and overlapped. This can explain that HSO has a higher hardness than HPO or HLERO, for a same SFC value, when diluted in LERO. Polymorphism was also observed by powder X-ray diffraction. The variability in hardness for samples having the same SFC is due to various crystal types and/or network structures that are formed upon crystallization of hard fats. This work demonstrates that for binary blends of studied oils, changes in the hardness are controlled mostly by the SFC, polymorphism and also by the material’s microstructure.     

葵花籽油基油凝胶在面包及冰淇淋产品中的应用研究

以葵花籽油为基料油,食品级植物蜡(米糠蜡、蜂蜡、棕榈蜡)作为凝胶剂构建油凝胶,分别以黄油、起酥油、葵花籽油作对照烘焙面包,以黄油、淡奶油作对照制备冰淇淋,对比分析不同油脂制作的面包和冰淇淋的感官及物性。结果表明:与对照组面包相比,油凝胶面包在各项指标上均无太大劣势,同时,油凝胶面包烘焙损失率比用传统黄油和起酥油烘焙面包小,且饱和脂肪酸含量降低;在抗融化性能方面,蜂蜡油凝胶冰淇淋和棕榈蜡油凝胶冰淇淋的抗融化性能好于黄油冰淇淋,但油凝胶冰淇淋膨胀率较低,不利于冰淇淋形成疏松绵软结构,且有少许蜡感,还需进一步改进。     

棕榈油与猪油在组成结构和功能特性上的比较

比较了3种棕榈油和6种猪油产品在理化指标、营养与功能特性指标以及脂肪酸组成及其在甘油三酯Sn-2位上的分布情况,以判断棕榈油对猪油的可替代性.结果表明,棕榈油和猪油的熔点、碘值、酸值、过氧化值等理化指标很接近;棕榈油不含胆固醇,具有比猪油较高的V_E含量和氧化稳定性;在可塑性方面,精炼棕榈油与猪板油相当,而且好于猪杂油和猪膘油,棕榈硬脂与猪骨油相当,棕榈液油与猪皮油相当;虽然棕榈油和猪油的脂肪酸组成具有相似性,猪油的不饱和脂肪酸含量略高于棕榈油的不饱和脂肪酸含量,但是棕榈油的Sn-2位上主要分布不饱和脂肪酸,而猪油的Sn-2位上主要分布饱和脂肪酸,使棕榈油比猪油更加容易消化吸收.     

Effect of oil type, temperature and time on moisture properties of hot oil-treated wood

This paper focuses on the moisture properties of wood treated in palm oil-, soy oil- and slack wax for different processing times and temperatures. Also, the relative importance of oil uptake and thermal modification on the wood moisture properties is investigated. Slack wax was better than palm oil or soy oil in improving the moisture performance of thermally treated wood, and treatment at 220 °C was superior to treatment at 200 °C, with 4 h being generally better than 2 h treatment. Water absorption in samples treated with wax at 100 °C or 160 °C was similar to that in samples treated at high temperatures while improved anti-shrink efficiencies (ASE) and lower hygroscopicities occurred only for the high temperature treatments. Chloroform extracted samples treated at high temperature with palm oil or soy oil had relatively similar hygroscopicity and ASE properties compared to unextracted samples, but had greatly increased water absorption properties. These results confirm that chemical reactions in wood resulting from the heat treatment account for the main improvements of wood properties in reduced hygroscopicity and improved dimensional stability, while the oil absorbed by wood reduces the rate of water absorption.     

若干物理因素对抗性淀粉制备的影响

抗性淀粉是一种新兴的食品添加剂,可作为食品的膳食纤维功能成分,广泛应用于碳水化合物、脂肪质食品如作为糖、面粉替代品,作为膳食纤维添加于焙烤食品、低热、低脂人造奶油、冷冻甜点等或作为一种单独的添加剂加入食品配方中。通过对制备过程中物理因素的研究,探讨了抗性淀粉的最佳制备物理条件,为工业开发应用提供一定的理论基础,抗性淀粉作为低热、高膳食纤维含量功能食品成分将具有重要的应用前景。     

Evaluation of shortenings based on various palm oil products

Several formulations based on blends of hydrogenated palm oil (MP 41·5°C) and palm stearin (IV 44) with other liquid oils, on direct blends of palm stearin with other liquid oils, and on 100% inter-esterified palm olein, were used as feedstocks in shortening production. The shortenings were stored at 20°C over a period of one month. Physicochemical characteristics, creaming properties and baking performance of the shortenings were evaluated and compared with the best shortening on the market. Slip melting point of the shortenings ranged from 41·5 to 46·4°C. Palm-cottonseed oil shortenings had higher solid fat contents at all temperatures than palm-soya bean or palm-low erucic acid rapeseed oil shortenings. The shortenings were rich in C₅₀, C₅₂and C₅₄ glycerides. Creaming power after 12 min of beating ranged from 1·55 to 1·77 cm³ g^?1. Palm stearin-cottonseed (3:2) oil shortening showed the best creaming performance. The specific volume of cakes ranged, for the experimental shortening, from 90% to 101% from the control, with low erucic acid-palm blends showing the best performance. In applications for both aerated cream and cakes, inter-esterified palm olein was excellent.     

Eating rate and preference of different concentrate components for cattle

Different feeds or combination of feeds were studied in 11 short-term experiments with the objective to identify concentrates that were especially desirable for cattle. Eating rate of different feeds was studied in 6 experiments using 10 heifers in a Latin square design with 2 blocks of 5 animals, 5 treatments (feeds), and 5 periods (days). Preference as shown by feed choice was studied in 5 experiments with 12 heifers. Paired comparisons of 4 different feeds (1 through 4) in the 6 possible combinations of 1 and 2, 1 and 3, 1 and 4, 2 and 3, 2 and 4, and 3 and 4 were performed. A control feed of ground barley was included in all experiments. In the eating rate and preference experiments, a total of 25 and 16 feeds, respectively, were studied. The categories of feeds studied were basic feeds, such as cereals, soybean meal, and rapeseed products, and feed mixtures based on ground barley with sweet additives or additives based on fat products. Pelleted concentrate mixtures were also evaluated. From the results obtained, the following feeds were identified as being among the most preferred feeds: pelleted feeds, heat-treated rapeseed meal, barley with 10% rapeseed fatty acid, barley with 10% palm oil, and barley with 10% glycerol, whereas ground palm kernel expeller was undesirable. A clear preference for pellets over ground barley was demonstrated, but no difference in preference was observed for the 3 different pellets that were compared.     

棕榈油在灯影牛肉丝中的应用研究

以熔点为24 ℃的棕榈油作为油炸用油,熔点为8 ℃的棕榈油和菜籽油调配后制作的红油来制作灯影牛肉丝。通过冷冻试验,确定用于灯影牛肉丝制作的红油中8 ℃棕榈油的最大添加量为30%。通过正交试验确定了灯影牛肉丝制作的最佳条件为腌制时间80 min,蒸肉时间1.0 h,在油温150 ℃条件下油炸90 s。在此最佳条件下,制作的灯影牛肉丝油润红亮、色泽均匀、风味纯正,感官评分为34.4分。结果表明,24 ℃棕榈油可用于灯影牛肉丝制作工艺中的油炸用油,质量分数为30% 的8 ℃棕榈油与菜籽油调配制备的红油可应用于灯影牛肉丝的制作。     

Effects of calcium salts differing in fatty acid composition on duodenal and milk fatty acid profiles in dairy cows

Ruminal biohydrogenation of fatty acids (FA) was studied in vivo in relation with the fermentation pattern in the rumen and milk secretion. Calcium salts (Ca salts) of palm oil (diet 1) or rapeseed oil (diet 2) were given to dairy cows (about 650 g day^?1) in a diet based on maize silage. Significant variation in propionate concentration was observed among diets. Rumen pH and total volatile fatty acids (VFA) did not change. Duodenal FA pattern was analysed throughout the day. With diets 1 and 2, linoleic acid was to a large extent biohydrogenated: calculations of ruminal biohydrogenation were equal to 63.6 and 74.0% for diets 1 and 2, respectively. No difference between diets was observed in milk production, fat and protein percentages. The percentages of stearic and octadecenoic FA in milk were higher and the percentage of palmitic acid was lower with Ca salts of rapeseed oil FA than with Ca salts of palm oil FA.     

The effects of industrial pre-frying and domestic cooking methods on the nutritional compositions and fatty acid profiles of two different frozen breaded foods

This study was carried out to determine the effects of manufacturer pre-frying in olive and sunflower oil, as well as domestic cooking methods (deep-frying in olive and sunflower oil and baking) on the proximate compositions and fatty acid profiles of tuna pasties and ham nuggets. The pre-frying processes reduced moisture and carbohydrates and increased ash, fat and protein content in both pre-fried products. During cooking, the frying processes caused a reduction in moisture content and an increase in fat content in relation to pre-fried samples, while baking did not modify the proximate composition. The fatty acid profiles of products during both the pre-frying and frying processes became similar to those of the culinary fat used. Thus, the frying processes reduced the proportion of saturated fatty acids (SFA) and increased the proportion of monounsaturated fatty acids (MUFA) in the foods when olive oil was used, whereas increased the proportion of polyunsaturated fatty acids (PUFA) in products fried in sunflower oil. The fatty acid profiles of fried samples tended to be more similar to the frying fat than to the pre-frying fat, whereas the fatty acid profiles identified during the pre-frying process for baked products were not significantly modified. Thus, samples pre-fried in olive oil and subsequently baked showed the best proportion of fat content and PUFA/SFA, MUFA + PUFA/SFA and n-6/n-3 ratios of the tested products.     

Crystallization and rheology of palm oil in the presence of sugar

Palm oil is an alternative to partially hydrogenated vegetables oils for fat-based confections given its semi-solid consistency and zero trans fat content. However, its slow crystallization behaviour results in hardening during storage and an objectionable texture. While there are numerous studies on palm oil solidification and storage properties in bulk, the impact of sugar in this context has yet to be reported. In this study, the crystallization and rheology of two commercial palm oils in both bulk and mixed 1:1 (wt.%) with confectioner's sugar were explored over four weeks of storage. The palm oil with the higher diacylglycerol and saturated triacylglycerol content experienced significantly higher solid fat contents and viscous/elastic moduli with storage time. The presence of sugar reduced the solid fat content of both palm oils, but increased their solid-like character, an effect we ascribed to the role of the dispersed sugar on oil viscosity. Principal component analysis on lipid composition identified the key species contributing to these properties. These findings establish a foundation for the optimization and improvement of palm-based confections.     

巧妙运用变性淀粉推动烘焙食品行业可持续发展的路径探索

淀粉是烘焙食品加工的主要原料,因其具有吸水膨胀等特性,可增加烘焙食品的含水量。但由于原生淀粉口感和稳定性较差,变性淀粉更多地被用于烘焙食品中,极大地改善了烘焙食品的口感和品质。基于此,介绍了变性淀粉的类型及其在烘焙食品中的应用现状,并提出了变性淀粉在烘焙食品中的发展策略。