Effects of processing conditions on the quality of vacuum‐fried carrot chips

The effects of pretreatment and vacuum frying conditions on the quality of fried carrot chips were studied. The moisture and oil contents of fried carrot chips were significantly (p < 0.05) reduced when blanched carrot slices were pretreated by immersion in fructose solution and freezing prior to vacuum frying. Furthermore, more uniform porosity was observed on the vertical cross‐section of carrot chips when examined by scanning electron microscopy. During vacuum frying, the moisture content, colour and breaking force of carrot chips decreased while the oil content increased with increasing frying temperature and time. However, there was no apparent change in Hunter ΔE with time when the frying temperature was below 100 °C and the frying time was below 25 min. Results of this study suggest that vacuum frying at moderate temperature (90–100 °C) for 20 min can produce carrot chips with lower moisture and oil contents as well as good colour and crispy texture. Copyright © 2005 Society of Chemical Industry     

Effects of type of packaging material on physicochemical and sensory characteristics of deep‐fat‐fried banana chips

A storage study of deep‐fat‐fried banana chips was carried out for 8 weeks at ambient temperature (27 °C), using four types of packaging material: laminated aluminium foil (LAF), oriented polypropylene (OPP), polypropylene (PP) and low‐density polyethylene (LDPE). The physicochemical and sensory characteristics of the stored banana chips were analysed at weeks 0, 2, 4, 6 and 8. The quality parameters determined were moisture content, water activity (a_w), thiobarbituric acid‐reactive substances (TBARS), texture (breaking force), colour and sensory attributes. The moisture content, a_w, TBARS and breaking force values of all samples increased during storage. The colour also changed during storage, showing higher L and lower a and b values. Samples packed in LAF had the lowest moisture content, a_w, TBARS and breaking force values. The most notable sensory change that occurred during storage was a decrease in crispness. Samples packed in LAF had higher scores than the other three samples, whilst LDPE gave the lowest scores for crispness as well as product colour. There were no significant differences (P > 0.05) in rancid odour among samples packed in OPP, PP and LDPE. However, there were significant differences (P < 0.05) between samples packed in LAF and the other three samples, with LAF giving the lowest rancid odour. © 2002 Society of Chemical Industry     

Effects of variety and stage of fruit ripeness on the physicochemical and sensory characteristics of deep‐fat‐fried banana chips

The quality of banana chips prepared from two different varieties of banana, Pisang Abu and Pisang Nangka, at the ‘green’ and ‘trace of yellow’ stages of ripeness was studied. The fruits were peeled, sliced to a thickness of 2 mm and deep‐fat fried in refined, bleached and deodorised (RBD) palm olein at 180 ± 5 °C for 3 min. The quality parameters determined for fresh bananas were total soluble solids, pH, acidity, carbohydrate, sugar content, fat, protein, moisture content, ash, fibre, colour and fruit firmness. The results showed that Abu had a higher carbohydrate content than Nangka at both stages of ripeness before frying. No sucrose was detected in Nangka. The quality parameters determined after deep‐fat frying were moisture content, water activity, oil absorption, crispness and sensory evaluation. The moisture content and water activity of Abu chips were lower than those of Nangka chips. The texture of chips prepared from Abu at stage ‘green’ showed more crispness than the other three samples. Sensory evaluation showed that chips prepared from Abu at both stages of ripeness presented better colour, flavour, odour, texture and overall acceptability than those prepared from Nangka. Based on the matrix of correlation coefficients, fresh bananas with higher fruit firmness and carbohydrate content gave banana chips with higher crispness and oil absorption. © 2001 Society of Chemical Industry     

降低油炸香蕉片含油率的研究

对油炸香蕉片含油率的影响因素进行了实验,结果表明：减少香蕉片含油率最佳工艺参数为脱油离心机转速500 r/min、浸涂添加剂海藻酸钠0.3%、果肉切片厚度3 mm。     

油炸香蕉片的等温吸湿规律及其热力学研究

为研究油炸香蕉片的热力学特性,理解油炸香蕉片在吸附过程中的水分变化和能量变化,采用静态称重法,测定了油炸香蕉片在10、25、40℃和六种不同水分活度下的吸湿特性,分别用6种吸附模型(GAB,Halsey,BET,Henderson,Peleg和Smith模型)进行拟合分析。结果表明,Peleg和GAB模型具有相对较高的拟合度,并根据GAB模型参数,获得了油炸香蕉片的单分子层水分含量。通过热力学方程得出了不同水分含量条件下的等量吸附热、微分熵,结果显示等量吸附热和微分熵都随水分的升高而减小,且两者呈线性关系。      

Effect of banana and soybean hull flours on vacuum‐packaged chicken nuggets during refrigeration storage

The green banana flour (GBF), soybean hull flour (SHF) and combination (50:50) of GBF and SHF were added at the level of 4% each to evaluate the storage characteristics of chicken nuggets. The pH values were declined (P < 0.05) over storage periods. Lipid oxidation products were higher (P < 0.05) in control samples; however, they were increased in all samples with the increase in storage time. GBF‐added samples had lower (P < 0.05) free fatty acid contents when compared to other treated nuggets including control. With respect to microbial quality, standard plate counts, psychrotrophic counts and Lactobacillus spp. counts were increased (P < 0.05) with the storage periods. Total coliforms, Staphylococcal spp. and Yeast and mould counts were detected sporadically. Result of sensory evaluation indicates that scores for all attributes were declined gradually with storage time, and slight off‐flavour was noticed on the day 45. So, chicken nuggets developed with GBF and SHF could have shelf life in between 36 and 45 days at 4 ± 1 °C under vacuum‐packaging conditions.     

油脂饱和度对油炸马铃薯片品质的影响

以玉米油、花生油、大豆油、大豆棕榈调和油、棕榈油5种不同饱和度油脂作为煎炸用油,以马铃薯片为煎炸内容物,于140℃循环煎炸。考察马铃薯片的油脂含量、水分含量、色泽、酥脆性以及感官评分的变化,综合分析油脂饱和度对油炸马铃薯片品质的影响。结果表明:煎炸油脂的饱和度显著影响油炸马铃薯片的品质(p 0.05),随着煎炸油脂饱和度的增加,油炸马铃薯片的油脂含量呈降低的趋势,水分含量呈增加的趋势,L值呈增大的趋势,表明马铃薯片颜色随着煎炸油脂饱和度的增加而越发鲜亮;油炸马铃薯片的酥脆性、感官评分亦随煎炸油脂饱和度的增加呈显著增加的趋势(p 0.05)。由此可知,相对于不饱和度较高的玉米油、花生油、大豆油,饱和度较高的棕榈油更加适合马铃薯片的煎炸。     

Evaluation of carrot varieties for production of deep fried carrot chips — II. Sensory aspects

Carrot variety had a significant (P ≤ 0.0005) influence on colour, sweet taste, fruity taste, acid taste, bitter taste, earthy taste, juiciness and crispness, while cultivation site (environmental conditions) had a significant (P ≤ 0.0005) influence on colour, sweet taste, bitter taste, earthy taste, aftertaste, juiciness and crispness. Sensory attributes of raw carrots could predict the quality of carrot chips by means of two factors when PLS has been applied. Factor 1 was explained mainly by cultivation site, but also by variety, while factor 2 was explained by variety.     

影响油炸薯片品质的工艺参数研究

对影响油炸薯片产品品质的工艺参数进行了研究。结果表明,油炸薯片的最佳工艺条件为：切片厚度控制在1．0～2．0mm,烘干时间为50-60min,油炸时间为2．0min,添加剂为0．3％CaCl2。     

Effects of maltodextrin level,frying temperature and time on the moisture,oil and beta‐carotene contents of vacuum‐fried apricot slices

Response surface methodology was used to investigate the effects of frying temperature, time and maltodextrin (MD) levels on the moisture, oil and beta‐carotene contents of the vacuum‐fried apricot slices. Based on the results, the moisture content of vacuum‐fried apricot slices decreases with increasing frying temperature and frying time. Generally, the oil content of vacuum‐fried apricot slices decreases with decreasing frying temperature and frying time. The beta‐carotene content of vacuum‐fried apricot slices increases with increasing frying temperature. But the trend of increase in the beta‐carotene content of the product with frying temperature was higher at lower MD level. When processing vacuum‐fried apricot slices, a frying temperature of 100 °C, frying time of 72.5 min and an MD level of 70% must be used to achieve a product of acceptable moisture, oil and beta‐carotene contents.     

Effect of cold pre‐treatment duration before freezing on frozen bread dough quality

The effect of cold pre‐treatment (CT) duration prior to freezing on the quality of a standard bread dough was investigated. Doughs held at 0 °C or 10 °C for 1 h or 3 h before air‐blast freezing were compared with standard dough frozen after 0.5 h at 0 °C (0 °C/0.5 h) and fresh (unfrozen) dough. Cumulative gas production measured in a risograph was used to quantify the dough quality after storage at ?18 ± 0.1 °C for 1, 7 or 17 days. Relative to fresh dough, gas production significantly reduced after freezing for all treatments. The doughs with CT at 0 °C for 1 or 3 h or 10 °C for 1 h had significantly higher gas production after freezing and less rapid decline in gas production during frozen storage than the doughs with the 0 °C/0.5 h CT. The 10 °C/3 h CT gave no gas production benefit after freezing and had the most rapid decline in gas production during frozen storage.     

Changes of microwave structure/dielectric properties during microwave freeze‐drying process banana chips

This experimental study investigated the trend of structure and dielectric properties during microwave freeze‐drying process banana chips. The mass of banana samples was 160 g, the microwave power set as 2 W g^?1 and the highest drying temperature set as 55 °C. The whole drying process can be finished within 6 h. A network analyser and light microscope were used to determine the dielectric properties and structure. The dielectric properties, ε′ (from 20.80 to 1.20) and ε′′ (from 7.74 to 0.15), and the size of cell get smaller as the drying process continues, especially during the 3–4 h drying, which is the end of primary drying stage and the beginning of secondary drying stage. The trend of dielectric properties and microstructure of samples during drying can be an exact indication of drying stage of MFD.     

Effect of dietary supplementation with vitamin E on characteristics of vacuum‐packed lamb

The effect of dietary vitamin E supplementation on lamb during vacuum‐packed storage was studied. Thirty‐six weaned male Manchego breed lambs were offered four dietary treatments (20, 270, 520 and 1020 mg vitamin E kg^?1 feed). Lambs were fed the vitamin E‐supplemented diet from 13 until 26 kg live weight. Pieces of M. longissimus dorsi were stored under vacuum at 2 ± 1 °C in the dark and meat quality was assessed after 5, 14 and 28 days of storage. Dietary supplementation significantly increased the α‐tocopherol concentration in the muscle (P < 0.001). Initially, lipid oxidation, meat colour and bacterial load were similar in all groups. In meat of non‐supplemented lambs the thiobarbituric acid reactive substance value increased throughout storage, whereas in meat of supplemented lambs it did not increase. Meat pigments and discolouration proportion were significantly affected by storage time (P < 0.001). The bacterial load was low initially, but after 28 days of storage it was close to 7 log₁₀ colony‐forming units (cfu) cm^?2 and Enterobacteriaceae surpassed the limit of acceptability of 2.5 log₁₀ cfu cm^?2, making the lamb unsuitable for human consumption. Meat of supplemented lambs displayed less lipid oxidation than that of their non‐supplemented counterparts, while meat colour and bacterial load were not affected by supplementation. Copyright © 2007 Society of Chemical Industry     

Effectiveness of antioxidants on the stability of banana chips

The effectiveness of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in improving the stability of banana chips stored at 65°C were compared. Criteria used in the assessment of the stability of the chips included the determinations of peroxide, p-anisidine, acid and iodine values, E_1cm ^1% at 232 amd 268 nm and the C18:2/C16:0 ratio of oil extracted from banana chips. It was found that chips fried in refined, bleached and deodorised (RBD) olein containing BHA or BHT were more stable than chips fried in RBD olein without antioxidants. BHT was more effective than BHA in prolonging the shelf-life of of banana chips. The same order of effectiveness of the antioxidants was observed at 65°C and at room temperature (25°C).     

Effect of vacuum cooking treatment on physicochemical and structural characteristics of purple‐flesh potato

Cook‐vide (CV, vacuum boiling) and sous‐vide (SV, cooking in a vacuum‐sealed pouch) have been applied to cook purple‐flesh potatoes. Response surface methodology (RSM) sets up the work conditions of temperatures (78–92 °C) and times (16–44 min). Textural parameters, colour and anthocyanins have been measured in cooked samples, and microstructure of cooked tissues was observed with cryo‐SEM technique. CV and SV provided similar hardness (P > 0.05), while SV treatments provided samples more adhesive and cohesive than CV ones (P ≤ 0.05). Micrographs of cooked samples showed rounder cells in cook‐vide samples and higher swelling than in sous‐vide ones. SV treatment avoided the leaching into the water of anthocyanins (chromophore) retaining more of them in potatoes (P ≤ 0.05), as a consequence of which total colour difference was lower in SV samples compared with CV ones (P ≤ 0.05). Particularly, CV samples were lighter (higher values of L*) and less reddish (lower values of +a*) than SV ones (P ≤ 0.05).