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     

Influence of the stage of ripeness of plantains and some cooking bananas on the sensory and physicochemical characteristics of processed products

The influence of the stage of ripening of the fruit of cultivars of plantain (French Sombre) and some cooking bananas (Dwarf Kalapua and Bluggoe) on the sensory and physico‐chemical characteristics of processed products was evaluated. Chips made from these cultivars at corresponding stages of ripeness had water contents less than 20 g kg^?1 for fruits at stages 1 and 3 and less than 60 g kg^?1 for those at stages 4 and 5. There was no significant difference (p > 0.05) between the ash contents of chips at different stages of ripeness for all the cultivars. Protein contents increased with increasing ripeness for all the cultivars; the fat contents decreased with increasing ripeness and varied from one cultivar to another. The available food energy was more than 4840 kcal kg^?1 of chips for all the cultivars at all stages of ripeness. The best chips were obtained from fruits at stages 1 and 3. Flours obtained from the fruits of these cultivars at different stages of ripeness had water contents lower than 60 g kg^?1. The fat, ash and protein contents were low, while the carbohydrate contents were high. For all the cultivars the yields of chips and flour were higher for the plantain cultivar (French Sombre) than for the cooking banana cultivars, irrespective of the stage of ripeness of the fruits. Cakes made from the different flours had good nutritional quality. The cakes and chips submitted for sensory evaluation were all accepted by consumers, although to differing extents. Fruits at stages 1 and 3 of ripeness which presented fewer problems during drying were the most suitable for the manufacture of flour for making cakes. Copyright © 2004 Society of Chemical Industry     

粉蕉后熟过程中香气品质变化及其关键基因表达特性

为深入了解粉蕉（Musa ABB Pisang Awak）采后品质变化特征,本实验研究了粉蕉（‘广粉一号’）采后常温（25?℃）贮藏过程中果实生理品质、不同成熟阶段果实香气物质变化及香气合成相关基因的表达特性。结果表明：粉蕉果实在采后2?d内硬度急剧下降,果实可溶性固形物质量分数以及可溶性糖含量都显著增加;果实在第6天完熟,第8天已经过熟,此阶段硬度降到很低,同时可溶性糖、总香气物质含量达到最高值,而可溶性固形物质量分数、氨基酸含量在第6天最高。未成熟粉蕉果实的挥发性物质种类及其含量较少,主要以C6～C9的醛类和醇类为主,而酯类极其微量;当果实完熟时挥发性物质含量明显增加,酯类含量明显上升,包括异丁酸异戊酯、乙酸己酯、乙酸异戊酯等,形成粉蕉特有的香气特征。对果实香气合成相关关键基因表达分析发现,脂氧合酶、醇酰基转移酶、醇脱氢酶、支链氨基酸转移酶和氢过氧化物裂解酶基因的表达随着果实成熟软化而增强,果实完熟后又迅速下降;丙酮酸脱羧酶基因的表达量在贮藏前期和后期较高,而在果实成熟的中期表达量很低,与果实在未熟期与过熟期醛类与醇类含量密切相关。本实验初步揭示粉蕉主要挥发性物质在成熟过程中的变化规律及其与相关生理活动的关系,为粉蕉采后的品质保持和保鲜技术提供了理论依据。     

Quality characteristics of refined,bleached and deodorized palm olein and banana chips after deep‐fat frying

The changes in quality characteristics of refined, bleached and deodorized (RBD) palm olein used for deep‐fat frying of banana chips (180°C for 3 min at 17 min intervals for 2 h day^?1, to give six fryings per day and 30 fryings over five consecutive days) were studied. Four frying systems were used: RBD palm olein without antioxidant (system 1); RBD palm olein with 0.2 g kg^?1 α‐tocopherol (system 2); RBD palm olein with 1 g kg^?1 oleoresin rosemary (system 3); and RBD palm olein with the combination of 0.1 g kg^?1 α‐tocopherol + 0.5 g kg^?1 oleoresin rosemary (system 4). Fried oil samples were analysed for fatty acid composition, peroxide value (PV), anisidine value (AnV), totox value, free fatty acids (FFA) value, iodine value, at 232 and 268 nm, colour and viscosity. The crispness and sensory evaluation of the banana chips fried in this study were also evaluated. The results showed that RBD palm olein with added antioxidant reduced PV, AnV, totox value, at 232 and 268 nm, FFA and viscosity. The order of effectiveness in inhibiting oil oxidation in RBD palm olein was: oleoresin rosemary > α tocopherol + oleoresin rosemary > α‐tocopherol > control. For the crispness, the force values of banana chips fried in all systems were comparable. Sensory evaluation of fried banana chips for each system showed that there was no significant (P > 0.05) difference in terms of colour, flavour, odour, texture and overall acceptability. Copyright © 2003 Society of Chemical Industry     

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     

Effect of superheated steam prefrying treatment on the quality of potato chips

Superheated steam drying (SSD) was used as a prefrying treatment prior to deep‐fat frying for potato slices. The effect of SSD at 130, 150 or 180 °C and steam velocity of 2.0 m s^?1 on the fat uptake, colour and texture of fried potato chips was evaluated; microstructure and degree of starch gelatinization were also evaluated to help explain the fat uptake results. SSD and frying yielded potato chips with the fat content from 0.263 ± 0.002 to 0.304 ± 0.002 kg kg^?1 (d.b.), while frying without SSD led to chips with the fat content as high as 0.359 ± 0.003 kg kg^?1 (d.b.). SSD did not promote starch gelatinization. Lower fat uptake was correlated to modified surface structure and lower moisture content of potato slices prior to frying. Frying with/without SSD pretreatment yielded potato chips of similar hardness, crispness and lightness. On the other hand, SSD significantly increased redness and yellowness of the fried chips.     

低温真空油炸粉葛片工艺优化及其品质分析

为实现粉葛的全质化利用,本文采用低温真空油炸工艺制备粉葛片。在单因素实验基础上通过正交试验优化了低温真空油炸粉葛片的制备工艺。结果表明,最优工艺为粉葛片厚度2 mm,油炸温度105℃,油炸时间35 min,漂烫时间3 min。在最优条件下粉葛片脆性值为989.35 g,脂肪含量为22.95%。此外,还比较了不同工艺制备的粉葛片品质。漂烫、冷冻处理后低温真空油炸粉葛片的脂肪含量较低,脆性值较高,而通过漂烫冷冻常规油炸所得粉葛片含水量（1.71%）和脆性值（597.54 g）最低,脂肪含量达62.24%。未漂烫粉葛片常规油炸后脂肪含量显著高于低温真空油炸所得粉葛片（P<0.05）,而脆性值无显著性差异（P>0.05）。油炸粉葛片香气物质以氮氧化合物、硫化物和有机硫化物为主,但是不同油炸所得粉葛片香味有明显差异。经油炸后粉葛片表面蜂窝状结构消失,通过漂烫冷冻低温真空油炸的粉葛片表面有少许孔洞,而在未冷冻的葛根片表面形成一层凝胶层。     

Deep‐fat frying of cassava: influence of raw material properties on chip quality

Thirteen cultivars of cassava (Manihot esculenta Crantz) were used to obtain chips by deep frying slices of fresh cassava flesh in palm oil. The cultivars were representative of three different levels of four major characteristics (water, cyanide, starch and amylose content) in parenchyma. The effects of raw material composition and crop age (10 and 12 months) on mass transfer (dehydration and oil uptake), texture and colour were assessed for 1.5 mm thick chips with a final water content of 0.04 kg kg⁻¹ wet basis, corresponding to a water activity of about 0.3. Frying time varied from 70 to 90 s and oil bath temperature from 140 to 160 °C. All cultivars gave a high frying yield (>0.5 kg chips kg⁻¹ fresh cassava) and a chip fat content of between 0.23 and 0.37 kg kg⁻¹ wet basis, with the highest frying yields and lowest fat contents being obtained from roots with the lowest water content and cyanide content. The intensity of darkening reactions increased in accordance with the level of reducing sugars, while the rigidity modulus of the chips was negatively correlated with the fibre content. The other characteristics (starch, amylose and total sugar content) were either not or poorly correlated with any of the chip quality parameters studied. Cyanoglucosides were only partially eliminated during frying (over 40% retention), so cultivars with a high cyanide content gave bitter chips. For a similar composition, drying rates and cooking rates were much lower when crop age increased. This could be attributed to a structural effect characterising crop age. © 2000 Society of Chemical Industry     

Porosity determination of deep‐fat‐fried coatings using pycnometer (Fried batter porosity determination by pycnometer)

The effect of processing conditions such as frying time and temperature, and batter formulation on pore development in deep‐fat fried chicken nuggets coatings were studied using helium pycnometer method. Chicken nuggets with preformed and laboratory prepared batter coatings were fried at temperatures between 170 and 190 °C for a time range between 0 and 240 s. There was significant (P < 0.05) effect of frying temperature and batter formulation on porosity. Porosity increased with frying time and temperature, and ranged between 2.15 and 47.92% for the preformed batter and 9.96 and 54.76% for the formulated batters. Apparent and bulk densities of the preformed batters increased and decreased with frying time, respectively, but both declined gradually with increasing frying temperature. As the level of rice flour in the formulation increased, apparent and bulk densities also increased. Batter formulation and frying temperature significantly (P < 0.05) influenced the variation in moisture and fat content of the fried batter. Porosity demonstrated positive and negative correlation with fat uptake and moisture loss, respectively, for all the batter coatings.     

The optimization of vacuum frying to dehydrate carrot chips

The effects of pretreatment and processing conditions, such as frying temperature, absolute vacuum pressure and frying time; on the properties of fried carrot chips were studied. Statistical analysis with response surface regression showed that moisture content, fat content and breaking force of carrot chips were significantly (P < 0.05) correlated with frying temperature, vacuum absolute pressure and frying time. The optimum conditions were a vacuum frying temperature of 100–110 °C, a vacuum absolute pressure of 0.010–0.020 MPa and a frying time of 15 min.     

Optimisation of processing variables in the preparation of sweet potato chips using response surface methodology

Models capable of predicting the product quality of sweet potato chips have been developed using response surface methodology and used to determine the optimum processing conditions. Moisture loss, oil uptake, crispness (measured using a bending-snapping test in the TA.XT2 Texture Analyser), and sensory attributes such as colour, flavour, and texture were used to assess the product quality in the preparation of sweet potato chips. The optimum conditions which were attained for maximum moisture loss (11.65% on wet basis), minimum oil uptake (2.57%), crispness (794.37 g), colour score (7), flavour score (7) and texture score (7) were: frying temperature, 174.7 °C; salt concentration, 0.45%; citric acid concentration, 0.37%; potassium metabisulphite concentration, 0.65%; and frying time, 26 s.     

The effect of the concentration of batter made from Chickpea (Cicer arietinum L.) flour on the quality of a deep-fried snack

Batters made from Chickpea (Cicer arietinum L.) flour and containing 36–44% solids were used to prepare a spherically shaped deep fat‐fried snack called boondi. The physical properties, such as colour and bulk density, chemical constituents such as moisture and fat content, and crispness were determined as was the sensory profile. Commercial samples of this popular snack were analyzed in a similar way. Boondi prepared with 40% solids in the batter had more desirable qualities such as uniformity, crispness and fried gram aroma. Those prepared from batters <40% solids were more porous, oily and less uniform in shape and gave rise to tear drop shaped boondi. At >40% concentration of solids boondi were more firm and less porous with a slight sandy note although the fat content was low. Principal component analysis revealed that among the six commercial samples three samples were found to be close to optimal quality while the other three were less satisfactory. Positive correlations were found for porosity, oily notes and fat content and negative correlations for firmness.     

Osmotic pre-treatment effect on fat intake reduction and eating quality of deep-fried plantain

The relationship between compositional changes during frying and an osmotic dehydration step before frying is described, including and explanation of their effects on eating quality of plantain chips. Three solutions were used to soak plantain slices (glucose, salt (NaCl) and glucose + salt) prior to deep-frying (170 °C). The temperature, moisture and fat changes during the frying were monitored, and the quality attributes and physicochemical properties were also determined. The osmotic pre-treatments had significant effects on most parameters of plantain chips. In general, treatments decreased oil intake, moisture content, and total volume and also reduced frying time, while the colour, rancidity, crispiness and sensory evaluation increased after 5 min of frying. However, a negative effect on high temperature induced colour development was observed for some of the treatments. Rancidity induction times were significantly higher for pre-treated samples, which is probably related to lower oil content, shorter frying times and lower water content.     

Variations in banana properties

Samples prepared from different bananas and from different parts of a banana may vary in their properties, which may cause variations in the final results in experiments. Therefore, assessment of variation in the samples’ properties is necessary, and it can be evaluated using statistical analysis. In this work, the variation in banana properties—colour, texture, moisture and sugar contents—within and between bananas were assessed statistically using a two-stage nested design test and the two-sample t-test. Results show that the variation of properties is significant for bananas with different degrees of ripeness. This finding suggests that samples can be prepared from different parts of the bananas provided that the bananas are at the same degrees of ripeness. It was also found that the location of sample in the drying chamber did not affect the measured properties of the drying bananas, significantly. The tests performed for banana texture using a laboratory apparatus produced results that were similar to those performed using a dynamic mechanical analyzer. This suggests that the use of highly-sophisticated instruments in the texture analysis of dried fruit in terms of the apparent modulus is not crucial.     

硫化氢对采后粉蕉果实贮藏品质的影响

为研究不同浓度硫化氢(Hydrogen sulfide,H₂S)处理对采后粉蕉果实品质的影响,将粉蕉果实分别用0.3、0.6和0.9 mmol/L NaHS溶液释放的H₂S处理,并定期观察和测定了贮藏期间果实的硬度、色泽、失重率、褐变指数、可溶性固形物(TSS)、可滴定酸(TA)、呼吸速率和乙烯生成速率。结果表明：H₂S处理明显延缓了粉蕉果实表皮黄化和果肉褐变指数的增加,减缓了果实的软化和失重率的上升,果实TSS含量以及TA含量上升幅度受到一定程度抑制。并且,除了TSS 3个不同浓度处理组间差别不显著外(P>0.05),其余都表现出0.6 mmol/L NaHS处理组效果更明显;与此同时,经NaHS处理还显著地抑制了果实的呼吸作用和乙烯生成速率的上升(P<0.05),推迟了呼吸和乙烯达到峰值的时间4 d。但不同浓度NaHS处理组间对乙烯影响不显著(P>0.05)。综合来看,不同浓度NaHS处理均可以延缓采后粉蕉果实的成熟衰老,其中以0.6 mmol/L NaHS处理的保鲜效果最明显。     

Physico-chemical and sensory properties of chips produced using different lupin (Lupinus albus L.) flour formulations and cooking methods

Development of novel snack foods is an important area of research, and different ingredients are being tested to develop and process new formulations. In this study, lupin chips prepared using different formulations (hulled lupin, whole lupin, wheat and corn flours) were cooked using baking and frying, and changes in the sensory and colour parameters, acrylamide contents, fat absorption, peroxide number and p-anisidine values of the final products were studied. Lupin flour significantly changed p-anisidine value of chips. Addition of lupin flour and cooking methods affected the colour, fat absorption and peroxide values. Significant differences in chemical properties of chips made from whole and hulled lupin flours were also observed. Acrylamide was not detected in all the formulations studied. The lupin chips have increased brightness (L*), no acrylamides, reduced peroxide and p-anisidine values and acceptable sensory quality; hence, this ingredient is recommendable for use in snack foods.     

Effects of vacuum frying on structural changes of bananas

Effects of oil temperature, frying time, and ripeness on dimensional changes of vacuum fried bananas were studied. Banana slices with cross section diameters of 25-30 mm and a thickness of 3.5-4.5 mm were fried at temperatures of 100, 110, and 120 °C and 8 kPa for 20 min to determine which temperature produced the highest degree of expansion. Using this temperature, the width and thickness of the product were measured at 0, 5, 10, 15, and 20 min to model the dimensional changes as a function of moisture ratio. Sensory evaluation was conducted using a 7-point hedonic scale test to determine the effect of ripeness on acceptability of the product. Scanning electron microscopy (SEM) was used to analyze the structure of the vacuum fried bananas.The experimental results under this vacuum pressure revealed that frying temperature of 110 °C on bananas at the second day of ripeness yielded the highest volume expansion. Sensory evaluations did not unveil any significant difference (p > 0.05) in acceptability of the products based on ripeness. Results from SEM exhibited, as a function of frying time, a dramatic increase in the pore size of the bananas, while the Heywood shape factor indicated an overall increase in the product volume.     

The effect of par‐baking and frozen storage time on the quality of cup cake

The effects of frozen storage and initial baking time of par‐baked cake on baking loss, volume, moisture, colour and textural properties of cake obtained after thawing and rebaking were investigated. Cakes, par‐baked at 175 °C for 15, 20 and 25 min, were stored at ?18 °C for 3, 6 and 9 months. After storage, par‐baked cakes were thawed and rebaked at 175 °C for 10, 15 and 20 min. Baking loss, moisture content, L and +b colour values, firmness, gumminess and chewiness of the resulting full‐baked cakes were significantly affected by both par‐baking and frozen storage time, while specific volume, cohesiveness, springiness and resilience values were significantly affected by frozen storage time. The increase in the time of frozen storage of the par‐baked cake leads to a decrease in the quality of the rebaked cake, namely an increase of baking loss and cake crumb firmness, and a loss in the moisture content and specific volume. Moisture of cake crumb, L and +b colour values, firmness, gumminess and chewiness significantly increased as the par‐baking time increased. However, regarding baking loss, specific volume, moisture content and textural properties, 3‐month intermediate storage at ?18 °C and 20‐min initial baking time gave the best result among the cakes produced by using the two‐step baking procedure.     

THERMAL and PHYSICAL PROPERTIES of TORTILLA CHIPS AS A FUNCTION of FRYING TIME

The objective of this study was to determine the thermal conductivity, specific heat, density (true and bulk), and the texture characteristics of tortilla chips and to study the effects of moisture content, oil content, and frying time on these properties. Tortilla chips were fried in fresh soybean oil for different times at 190C. Results showed that the values of thermal conductivity of tortilla chips decreased from 0.23 to 0.09 W/mC, specific heat from 3.36 to 2.31 kJ/kgC, and bulk density from 880 to 579 kg/m³ as frying time increased. In general, the crispness of tortilla chips increased as frying time increased.     

Consumer perceptions of bananas treated with ethylene or allowed to ripen naturally

Consumers evaluated the eating quality and appearance of commercially available (ethylene treated) bananas and bananas which were allowed to ripen naturally (without ethylene). Quantitative measures of sweetness, liking when eaten, ripe taste, softness, flesh yellowness, liking of skin colour and skin yellowness were collected for bananas at three different stages of ripeness as judged by skin colour. Whole and peeled bananas were provided separately. Multivariate analysis of the combined data revealed that consumers discriminate between fruit using liking of skin colour and softness. Consumers like the taste of ripe fruit, but like the appearance of unripe fruit. Consumers were also able to detect that at a certain stage of skin colour ripeness, ethylene treatment results in bananas with flesh ripeness out of phase with skin colour ripeness.