Design, Construction, and Testing of an Automated NIR In-line Analysis System for Potatoes. Part II. Development and Testing of the Automated Semi-industrial System with In-line NIR for the Characterization of Potatoes

An automated semi-industrial system with in-line near-infrared reflectance (NIR) for the characterization of the chemical composition of potatoes was designed and constructed, and its performance was tested. The system consisted of the following subsystems: sample crate manipulator, weighing unit for the gross sample weight, potato washing machines with a washing water recycling system, belt for visual inspection of the potatoes, unit for measuring the underwater weight (UWW), industrial rotary saw blade rasp for pulping the potatoes equipped with a sulfite dosage system for inhibiting enzymatic browning of the pulped potatoes, and industrial NIR system for the measurement of the potato composition. The whole system was controlled and operated by a programmable logic controller and process personal computer system. The system was able to process 12 potato samples per hour. Measurements were done to establish the sample carry-over in the system. The carry-over was proven to be well below the maximum acceptable level of 2%. The UWW values established with the automatic system corresponded very well with the UWW data obtained by manual weighting. The day-to-day reproducibility of the UWW system was tested with golf balls. These balls have about the same specific gravity and size as potatoes. The day-to-day reproducibility coefficient of variation of the UWW unit was 0.4%. As a principle of proof, two tentative partial least squares calibration models, one for the starch concentration and one for the coagulating protein concentration in the potato samples, were calculated, applying leaving one out cross-validation. Both models were very promising. The by NIR-predicted starch concentrations showed to be at least as good or even better than the by UWW-obtained starch concentrations. The average difference between the by NIR-predicted and the chemically measured starch concentration was 0.0 ± 0.3% (w/w). For the coagulating protein concentration, the average difference between the by NIR-predicted and the chemically measured concentration was 0.00 ± 0.06% (w/w). In future years, potatoes of a wider range of varieties, growing locations, and growing seasons have to be added to the present tentative model, in order to get a robust NIR model.     

Effects of Baking and Boiling on the Nutritional and Antioxidant Properties of Sweet Potato [<Emphasis Type="Italic">Ipomoea batatas</Emphasis> (L.) Lam.] Cultivars

The effects of baking and boiling on the nutritional and antioxidant properties of three sweet potato cultivars (Beniazuma, Koganesengan, Kotobuki) cultivated in Turkey were investigated. The samples were analyzed for proximate composition, total phenolic content, ascorbic acid, β-carotene, antiradical activity, and free sugars. The dry matter, protein, and starch contents of the sweet potatoes were significantly changed by the treatments while the ash and crude fiber contents did not differ as significantly. The β-carotene contents of baked and boiled sweet potatoes were lower than those of fresh sweet potatoes; however, the total phenolic and ascorbic acid contents of the baked and boiled sweet potatoes were higher than those of the fresh samples. Generally, the antiradical activity of the sweet potatoes increased with the treatments. Sucrose, glucose, and fructose were quantified as free sugars in all fresh sweet potatoes; however, maltose was determined in the treated samples. In terms of the analyzed parameters, there were no explicit differences among the sweet potato cultivars.     

Tuber and starch quality of wild and cultivated potato species and cultivars

Summary Between 1993 and 1998 205 different potato cultivars and 1220 accessions/genotypes of wild and cultivated potato species from the IPK Genebank Gatersleben were evaluated. Parameters interesting for starch isolation and especially for the use of starch were determined. Altogether, there was a higher variability in wild potato species than in cultivated potatoes for all characteristics investigated: dry matter content, starch content, protein content, amylose content and mean particle diameter of starch granules.     

山体库与恒温库马铃薯贮藏比较试验

以当地主栽的马铃薯品种大西洋、克新19号为材料,于2007年9月至2008年5月进行了山体库和恒温库贮藏比较试验,比较山体库与恒温库马铃薯不同贮藏时期温度、湿度变化与干物质、淀粉、还原糖的含量及变化。试验结果表明:山体库贮藏马铃薯期间温度、湿度的变化不大,通风情况良好,贮藏的薯块没有出现发热、失水现象。经多次分品种进行还原糖含量、淀粉含量和干物质含量三项理化指标的测定,测定结果都符合马铃薯种薯和商品薯贮藏标准。在马铃薯加工利用时,对于山体库低温长时间存贮的马铃薯根据加工利用目的,如淀粉加工、食品加工必须进行升温贮藏;山体库与恒温库在3℃条件下贮藏的马铃薯各项指标变化趋势一致,符合马铃薯种子和商品薯贮藏标准,在冷凉地区适合山体库推广应用。     

Diffusion-processed sweet potato pulp,a new product with broad appeal

Peeled sweet potato slices of two standard varieties were soaked for 120 min, drained, boiled for 20 min, and mashed. The pulp was prepared in 6 simple dishes and tested organoleptically by a trained taste panel. The pulp was also prepared and evaluated by 30 families. Sugar and protein contents were compared to those of untreated uncooked sweet potato, and untreated cooked sweet potato. Diffusion processing lowers the content of all sugars, but subsequent cooking increases reducing sugar content. Processing also removes water soluble phenolic substances and results in less polyphenolic discoloration before and after cooking. Protein and starch contents are also reduced, the former by diffusion, and the latter by diffusion and by erosion on boiling. Dishes made from the pulp were highly acceptable, more moist in texture, less sweet, and more attractive than dishes from non-processed sweet potatoes. People who do not like to eat sweet potatoes found diffusion processed pulp highly acceptable as a staple food.     

NIR determination of potato constituents

Summary The development of a method of NIR (near infrared) spectrometric analysis to measure the quality determining constituents of potatoes and the accuracy of its performance are presented. The results show that it is possible to obtain quantitative information about different constituents from reflectance measurement of homogenized peeled potatoes. The analytical performance of NIR spectrometry is highly dependent on the cultivar being measured. Consequently, the calibration and validation sample sets will have to be expanded to provide greater utility.     

Estimation of dry matter and starch concentration in potatoes by determination of under-water weight and near infrared spectroscopy

Summary Potato food and non-food industries need information about dry matter (DM) and starch concentration of tubers. Therefore, calculation of dry matter concentration and starch concentration via under-water weight were optimised. Determination coefficients (R²) were 0.92 and 0.83 (starch concentration between 13 and 23%), and 0.94 and 0.88 (starch concentration ≥13%) for dry matter and starch concentration, respectively. In a second attempt, near infrared spectroscopy models for both constituents were calculated (R² of validation set was 0.98 and 0.96 for dry matter and starch concentration, respectively). Results pointed out superiority of the near infrared technique with less divergence than the techniques of under-water weighting.     

马铃薯块茎产量淀粉与土壤质地含水量的关系

试验在1992年同时安排在河北坝上、山西大同和内蒙呼盟进行。每个地区选用3个品种（系）种植在当地典型沙土和粘土，并施以“常干旱”和“常湿润”两个处理以观察土壤质地和水分含量对马铃薯淀粉含量的影响。试验结果表明：“常湿润”处理的马铃薯的产量显著高于“常干旱”的处理，而两者的淀粉含量没有明显差别。综合分析，沙土地的产量在“常干旱”情况下低于粘土地的产量，而在“常湿润”条件下则高于粘土地的产量。块茎的淀粉含量总的来分析，沙土地的要等于和高于粘土地，最多可高出2％以上。马铃薯品种不同，其淀粉含量多寡对土壤沙粘的水分含量的要求也不相同。品系“坝318”淀粉含量在“常干旱”处理条件下常高于“常湿润”处理，而“晋薯2号”则正相反。     

大麦籽粒抗性淀粉含量快速测定方法研究

为探索快速高效测定大麦籽粒中抗性淀粉含量的方法,利用衰减全反射中红外（attenuated total reflection mid-infrared spectroscopy,ATR-MIR）和近红外（near-infrared spectroscopy,NIR）光谱技术,分别用3种不同方法进行预处理,建立大麦样品的抗性淀粉含量快速测定红外模型,通过不同预处理预测模型的校正和内部交叉验证结果的比较,依据决定系数（r）和均方根误差（RMSE）筛选出基于ATR-MIR和NIR光谱的最佳预测模型,再对最佳预测模型进行外部验证。结果表明,经基线位移校正+范围归一化（BOC+RN）预处理后的PLS模型为最佳ATR-MIR预测模型;经标准正态变换+Savitzky-Golay法一阶求导（SNV+1thD）的预处理模型为最佳NIR预测模型。用验证集材料对BOC+RN和SNV+1thD最佳预测模型的预测效果进行外部验证,光谱预测值与化学测定值之间没有显著差异,说明两种方法均可以用于大麦籽粒抗性淀粉含量测定;ATR-MIR光谱比NIR光谱具有更好的预测能力。     

Soft-rot Resistance of Coloured Potato Cultivars (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.): The Role of Anthocyanins

Coloured potatoes (Solanum tuberosum L.) rich in anthocyanins are gaining increasing interest on the markets, mainly due to beneficial health effects. Potato varieties containing colour pigments are therefore utilized more and more in actual breeding programmes. In this study, 10 purple-fleshed potato cultivars were compared in their resistance to soft rot caused by Pectobacterium carotovorum (Pc) with 10 white/yellow-fleshed potato cultivars. The results revealed that coloured potato cultivars exhibited on average better resistance to soft rot than white/yellow-fleshed potato cultivars. On tuber halves of purple-fleshed cultivars, the extent of rotting caused by Pc was on average 28.6% lower than on white/yellow-fleshed cultivars. The greater resistance of coloured potatoes coincided with the presence of anthocyanins, higher concentrations of soluble phenols and elevated polyphenol oxidase activity in tuber tissue. These three components were significantly correlated with the extent of rotting caused by Pc. However, coloured and white/yellow-fleshed cultivars were not very different in phenylalanine ammonia-lyase and peroxidase activity. There were also no significant differences in concentrations of dry matter, starch, crude protein and glycoalkaloids. Key findings reveal that total soluble phenols and anthocyanins contributed crucially to resistance expression in tuber tissue of coloured potato cultivars.     

The development of translucent end tubers

A study was made to gain greater understanding of the development of translucent end tubers which caused problems for french fry processors duringthe processing season of 1971–72. Analysis of seven commercial and three experimental samples revealed a lower dry matter and higher reducing sugar content in the basal portion of the tubers. Normally Russet Burbank potatoes contain higher dry matter in the basal end. A study of dry matter changes during growth and development in 1971 and of moisture stressed potatoes in 1972 showed a reversal in dry matter content and an uneven distribution of reducing sugars, whereas the normally irrigated potatoes maintained a higher percentage of dry matter in the basal portion throughout. A decrease in pH of the tissue accompanied the loss of starch from the basal portion of moisture stressed potatoes. As postulated by other research workers, the loss of dry matter is attributed to initiation of active growth of the apical end, thereby utilizing carbohydrates from the basal end following a period of stress. Immaturity of tubers and storage at low temperatures immediately after harvest caused water stressed potatoes to develop increased numbers of translucent ends in storage.     

Fractionation of oats into products enriched with protein,beta-glucan,starch, or other carbohydrates

A modified wet method was developed to fractionate ground oat groats into 4 fractions enriched with beta-glucan (BG), protein, starch, and other carbohydrates (CHO), respectively. Effects of defatting oats and centrifuge force for separation were also investigated. Results show that, depending on the two factors, nutrient concentrations in the corresponding fractions ranged 28.53–44.84% (dry matter) for BG, 72.41–92.62% for protein, 79.13–81.69% for starch, and 37.47–42.16% for other CHO. Nutrient recoveries from each fraction were 39.82–51.20% for BG, 60.36–72.08% for protein, 77.04–87.25% for starch, and 24.87–29.68% for other CHO. For the protein fraction, defatting improved the protein content but did not on its recovery. For the starch fraction, the effect of defatting was just opposite, improving the starch recovery but not the starch content. Centrifuge force increased the BG content in the BG fraction when the defatted sample was used. The cumulative recovery of each component in the combined fractions was not affected by oil removal or centrifuge force. Overall, the wet method described was relatively effective in recovering the major nutrients from oats into their respective fractions, while it alleviated the problems of viscous slurry upon mixing ground oat groats with an alkaline solvent and the difficulty of slurry separation.     

Cool Farm Tool – Potato: Model Description and Performance of Four Production Systems

The Cool Farm Tool – Potato (CFT-Potato) is a spreadsheet programme that allows the calculation of the amount of CO₂ equivalents that it costs to produce 1 t of potato. The spreadsheet was adapted from an original generic version of the tool, and completed for potato production in diverse production areas in the world applying different levels of technology. The CO₂ embedded in chemicals during their production and released from the soil after nitrogen fertilization in the CFT-Potato has been updated to consider more recent products and production methods. Energy costs of the operations in the original version taken from generic data provided by the American Society of Agricultural and Biological Engineers Standard, however, were altered (usually increased) where there was evidence from practical sources that the original figures did not apply. For example, the figure of around 16 l of diesel per ha for potato harvesting in the original version was corrected to 60 l of diesel per ha based on observational data. Figures for typical potato operations such as windrowing were supplied. Irrigation with pumps powered by diesel or electricity from the grid, with a centre pivot, a rain gun, drip irrigation and flooding and energy cost for extracting water from deeper sources were also added. We added data for grading, washing, store loading and unloading, the application of a sprout suppressant and storage with ventilation of ambient air or forced refrigeration. The CFT-Potato can be used by growers to calculate the actual costs of 1 t of potato in terms of kilograms CO₂ and explore the repercussion of altered management options. Here the comparison of four potato production systems in the Netherlands is shown: seed potatoes (115 kg CO₂/t), table potatoes (77 kg CO₂/t), starch potatoes (71 kg CO₂/t) and organic potato (82 kg CO₂/t). Based on potato dry matter, however, starch potato has the lowest footprint mainly due to the extensive use of pig slurry of which the production and transport CO₂ costs are attributed to the pig production chain.     

Protein and starch digestibilities and mineral availability of products developed from potato,soy and corn flour

A technique for development of potato flour was standardized. Five products viz. cake, biscuit, weaning food, panjiri and ladoo were prepared incorporating potato flour, defatted soy flour and corn flour. Baking and roasting were the major processing techniques employed for the development of these products. Protein, ash and fat contents of potato flour were almost similar to those of raw potatoes. Significant differences in protein, ash and fat contents of all the products were observed. Protein and starch digestibility of potato flour was significantly higher than that of raw potatoes. Protein digestibility increased by 12 to 17 percent on baking or roasting of products. Processed products had significantly higher starch digestibility and mineral availability compared to raw products. Thus, it can be concluded that roasting and baking are effective means of improving starch and protein digestibility and mineral availability of products.     

A non-destructive method for rapid evaluation of boiling quality of potato tubers

A non-destructive method for rapid evaluation of boiling quality of potatoes has been developed. The method is based on the degree of sloughing, after-cooking darkening and colour of tuber fractions (cores of 1.3 cm in diameter) cooked in test tubes at 118°C for 25 min. Using sixteen potato cultivars, with 20–30% dry matter content, boiling quality results obtained by the new method were compared to sloughing and after-cooking darkening values obtained by boiling quartered tubers in aluminum sauce pans on a standard electric stove. The correlation coefficient between sloughing data obtained by the two methods was 0.912 (P< -0.001). The new method has proven to be simple, reproducible and highly suitable for evaluating a large number of potato samples. This should make it attractive for routine use by potato breeders.     

不同窖藏条件下马铃薯块茎营养物质含量的变化

以克新1号为供试材料,研究了4种不同窖藏条件下马铃薯块茎中干物质、淀粉、还原糖、Vc、可溶性蛋白含量的变化。结果表明:在4种不同窖藏条件下,马铃薯块茎中干物质、淀粉、还原糖、Vc、可溶性蛋白含量变化趋势相同,但变化幅度不同。窖内平均温度越高,湿度越小,块茎干物质、Vc、可溶性蛋白含量降低幅度越大,而淀粉含量降低幅度与还原糖增加幅度越小;反之,窖内平均温度越低,湿度越大,块茎干物质、Vc、可溶性蛋白含量降低幅度越小,淀粉含量降低幅度与还原糖含量增加幅度越大。     

Crude Protein Content in Diploid Hybrid Potato Clones of Solanum phureja–S. stenotomum

Breeding potato (Solanum tuberosum L.) with high protein content is important for food value and for the processing sector to extract protein from potatoes. Due to the narrow genetic base of the common potato, a new germplasm has to be explored for breeding high-protein potatoes. The objectives of this research were to quantify the crude protein content of diploid hybrid Solanum phureja–Solanum stenotomum (PHU-STN) genotypes, determine the correlation of crude protein content with dry matter and other important agronomic traits, and estimate broad sense heritability for crude protein content. In 2008 and 2009, 70 diploid clones were grown in replicated field plots in Jiagedaqi, Heilongjiang. Also, two tetraploid potato cultivars, Kexin 2 (table potato) and Atlantic (high dry matter), were included in this experiment as controls. The crude protein content on a fresh weight basis (FW) over replications and years for PHU-STN clones ranged from 2.85% to 5.01% with a grand mean of 3.72%, and most of these clones were significantly or highly significantly higher in crude protein content than the two tetraploid controls. Correlations between crude protein content and agronomic traits were all negative, but the magnitudes were generally weak or moderate. Therefore it should be possible to select diploid clones with high crude protein content and acceptable agronomic traits. The estimate of broad sense heritability for crude protein content (FW) on a clonal mean basis was 0.66 with a 95% confidence interval of 0.46 to 0.79, whereas for crude protein content on a dry weight basis the estimate of broad sense heritability was 0.65 with a 95% confidence interval of 0.43 to 0.78. These results suggest that these diploid hybrid PHU-STN clones would be a good germplasm source for a high-protein-breeding effort, and identification of tetraploid progenies with high protein content and acceptable agronomic traits from 4x–2x cross should be possible.     

Evaluation of potato cooking quality in Argentina

Cooking quality of mature tubers was assessed for ten Argentine potato cultivars, two cultivars of foreign origin and three advanced clones. Specific gravity, dry matter and starch content, as well as quality of boiled potatoes and chips were determined Pampeana INTA had the highest dry matter content with 21.8 percent and would appear to be a very good cultivar for dehydrated products. The lowest dry matter values were obtained for three of the four most widely planted cultivars: Spunta, Bonaerense La Ballenera and Kennebec Kennebec demonstrated its good quality for chipping with a score of 6.9 points. Primicia INTA and Sureña INTA with high dry matter content and good features for chipping can also be used to produce chips Breeding under high temperatures during tuberization has proven to be a successful strategy in developing cultivars that are superior in dry matter contents to the cultivars currently imported from the northern hemisphere     

Some characteristics of the Freeze-Thaw process for potato granule production

Netted Gem potatoes of 1.095 S.G. (24% dry matter) and 1.080 S.G. (19.1% dry matter) were processed using the recently developed Freeze-Thaw (F-T) process. There was an efficient reduction of moisture during the pre-drying step due to the long constant rate period. Short and rigorous granulation, which followed the pre-drying, took place under optimum conditions (when the potato cells were most resistant to shear and compression) during which the moisture content was slowly reduced through the critical range of 45% to 35%. The result was a high amount of fine granules (approx. 90% of < 60 mesh), a low amount of discard (≤2% of > 18 mesh) and a low amount of broken cells (≤2%). The experiments also showed that the F-T process could handle potatoes with low as well as high dry matter content.     

Prediction of total phenols,condensed tannins,and 3-deoxyanthocyanidins in sorghum grain using near-infrared (NIR) spectroscopy

The reported high phenolic levels in sorghum have led an interest from sorghum breeding programs in developing and identifying germplasms with high phenolic levels, which require screening a large number of samples to find those with the highest levels. Since wet chemistry screening methods are slow, expensive, and destructive, the use of NIR calibration curves could be an alternative. The objectives of this project were to determine the variation range in total phenols, condensed tannins, and 3-deoxyanthocyanidin levels in a diverse set of sorghum genotypes and to assess the predictive value of NIR curves to estimate these compounds in sorghum. A calibration curve to estimate each compound was developed and validated with an independent validation set. Calibration curve correlations for total phenols, condensed tannins, and 3-deoxyanthocyanidins were r = 0.98, 0.97, and 0.99, respectively. Correlations between NIR-predicted values and reference values in the validation set were significant for total phenols (r = 0.93), condensed tannins (r = 0.81) and 3-deoxyanthocyanidin (r = 0.82). These indicated that sufficient variation for these compounds existed within sorghum and that NIR calibration curves could be used to rapidly and non-destructively predict total phenols, condensed tannins, and 3-deoxyanthocyanidins concentrations in whole grain sorghum.