Tuber quality and nutritional components of “early” potato subjected to chemical haulm desiccation

Optimization of vine killing date for maximum seed-tuber yield and minimum exposure to late-season aphid vectors in potato

Short-duration and early-bulking potato varieties are well-suited for commercial cultivation in the subtropical Indo-Gangetic plains of India. To maximize seed tuber yield, prevent late-season exposure to aphid vectors, and facilitate the timely planting of wheat crops during the rabi season, it is essential to cut the haulms (vines) of seed potatoes at the earliest possible time. A study was conducted to standardize the optimal vine-killing date for two popular potato varieties in the north-western plains of India, Kufri Pukhraj and Kufri Jyoti, by examining variations in seed yield across different vine-killing dates and assessing the incidence of aphid vectors transmitting potato viruses. Tubers were planted on 15 October for two consecutive seasons, and haulms were cut at 70, 80, and 90 days after planting (DAP), with continuous monitoring of aphid populations. Results showed that total tuber yield and tuber numbers increased with delayed vine-killing. Similarly, the yield and number of oversized tubers significantly rose as the vine-killing date was extended. However, seed-size and undersized tuber yields were largely unaffected, while the number of undersized tubers decreased between 70 and 90 DAP. Further, the gain in total tuber yield and yield of over-sized tubers occurred mainly during 70-80 DAP for Kufri Pukhraj in contrast to Kufri Jyoti where maximum increase occurred between 80 and 90 DAP. Therefore, it is concluded that the optimum time of vine killing for maximum seed tuber yield is directly linked to the tuber growth cycle of individual variety. The period of maximum incidence of aphid vectors varied between the two years. Based on the incidence of Myzus persicae, the seed crops in north-western plains of India should not be extended beyond last week of December although real time monitoring of the aphid incidence is recommended.

Potato Processing Industry in China: Current Scenario, Future Trends and Global Impact

Potatoes play an important role in ensuring food security. During the COVID-19 epidemic, consumption of processed potato products decreased, and consumption of fresh potatoes increased. China is the world's largest potato producer with more than 4.81 million hectares of area under potato production and 90.32 million metric tonnes of potatoes produced in 2018. This accounts for 27.36% of the world's planting area and 24.53% of the world's potato production. The proportion of potatoes processed in China was about 12% in 2017, mostly dominated by starch production. However, the recent policy of the Chinese government to popularise potato as a staple food has created new markets for processed potato products other than starch. A very few reports have analysed these future trends of the rapidly growing Chinese potato processing industry and its impact within and outside China. This paper provides an overview of the latest developments with a focus on processed potato products such as potato chips, French fries and dehydrated potatoes, and also, due to the unique Chinese diet culture, it highlights the need for more scientific research dedicated towards the development of novel potato-based healthy foods.

Nitrate, nitrite and nitrosamines in the global food supply

Inorganic nitrate provided by either nitrate salts or food supplements may improve cardiometabolic health. However, current methods to assess dietary nitrate, nitrite and nitrosamine consumption are inadequate. The purpose of this study was to develop a reference database to estimate the levels of nitrate, nitrite and nitrosamines in the global food supply. A systematic literature search was undertaken; of the 5,747 articles screened, 448 met the inclusion criteria. The final database included data for 1,980 food and beverages from 65 different countries. There were 5,105 unique records for nitrate, 2,707 for nitrite, and 954 for nitrosamine. For ease of use, data were sorted into 12 categories; regarding nitrate and nitrite concentrations in food and beverages, 'vegetables and herbs' were most reported in the literature (n = 3,268 and n = 1,200, respectively). For nitrosamines, 'protein foods of animal origin' were most reported (n = 398 records). This database will allow researchers and practitioners to confidently estimate dietary intake of nitrate, nitrite and nitrosamines. When paired with health data, our database can be used to investigate associations between nitrate intake and health outcomes, and/or exercise performance and could support the development of key dietary nitrate intake guidelines.

Plant Cover Stimulates Quicker Dry Matter Accumulation in “Early” Potato Cultivars without Affecting Nutritional or Sensory Quality

“Early” potato crops are grown in the Mediterranean basin and are marketed from March to June, well before main-crop potato in the spring–summer growth period. Different growing technologies have been implemented to enhance potato “earliness” to achieve a better market price, but at the same time, the applied technologies may influence yield and quality of the ‘early potato’. The main goal of this study was to investigate differences in “early” potato nutritional and sensory characteristics after oil-frying influenced by location and plant covering in five potato cultivars. The present investigation was carried out at two planting locations during two seasons. The application of a plant cover significantly increased the potato tubers’ dry matter, starch, and sugar content in the second season. Sensory analysis of the oil-fried “early” potatoes revealed no differences between potatoes grown with or without the plant cover. We also observed significantly higher dry matter content in potatoes grown at the Split location in the second year, while no differences in the sensory scores between oil-fried potatoes grown at the investigated locations were observed. By employing a plant cover or by choosing a warmer planting location the desired potato maturity level could be reached in less time, and one could more effectively exploit the “early” potato market. By employing such techniques there should be no loss in yield, nutritional or sensory quality of potato tubers.

Physiological response of two olive cultivars to secondary metabolites of Verticillium dahliae Kleb

The effects of two purified fractions (formerly D-SXM and ND-SXM) produced in vitro by defoliating (Vd312D) and non-defoliating (Vd315ND) strains of Verticillium dahliae were studied on twigs of Olea europaea cvs Frantoio and Leccino. Symptoms, such as leaf curling, yellowing, vein clearing and defoliation, which are observed on the two cultivars naturally affected by Verticillium wilt, were produced by these fractions. Physiological changes were induced during the first seven days after the absorption of solutions containing ND-SXM or D-SXM. Both fractions increased the transpiration flow from abaxial leaf surfaces. Cell membrane and antioxidant activity were the most important action sites of ND-SXM and D-SXM. ND-SXM influenced malondialdehyde concentration in 'Leccino' leaves, while D-SXM increased the percentage of electrolyte leakage in 'Frantoio'. Both fractions reduced the total non-enzymatic antioxidant activity on the leaves of the treated twigs. The total phenol content increased in both cultivars, without differences to the control. Variations on electrolyte leakage and total antioxidant activity were effective in discriminating the two tested olive cultivars for V. dahliae tolerance or susceptibility. If V. dahliae strains Vd315ND and Vd312D produce ND-SXM and D-SXM in the infected plants, these metabolites may move via the xylem sap, accumulate in the leaves and induce changes that will lead symptoms on the leaf by compromising the cell membranes physiology.

Physicochemical Characteristics and Composition of Three Morphotypes of Cyperus esculentus Tubers and Tuber Oils

Tuber characteristics and nutrient composition of three morphotypes of Cyperus esculentus tubers and tuber oils were determined. The mean value for length and width of the tuber and one thousand dried tuber weights ranged from 0.98 to 1.31 cm, 0.90 to 1.19 cm, and 598 to 1044 g, respectively. Tubers displayed high level of starch (30.54-33.21 g 100 g(-1)), lipid (24.91-28.94 g 100 g(-1)), and sucrose (17.98-20.39 g 100 g(-1)). The yellow tubers had significantly higher content in lipid compared to black ones. Levels of ascorbic acid, tocopherol, and β-carotene of the three morphotypes differed significantly. Yellow ones (morphotypes 1 and 2) were the richest in tocopherol and the poorest in β-carotene. Saturated fatty acid content of morphotype 2 was significantly lower than that of morphotypes 1 and 3. Morphotype 3 had the significantly lowest PUFA content compared to morphotypes 1 and 2. Morphotype 1 was found to be richer in Ca, Cu, and Mn contents. Al, Mg, P, S, and Si were most abundant in morphotype 2. Morphotype 3 had the highest content of Cl, K, and Zn.

Ascorbic acid contents in transgenic potato plants overexpressing two dehydroascorbate reductase genes

Ascorbic acid (AsA, vitamin C) is one of the most important nutritional quality factors in many horticultural crops and has many biological activities in the human body. Dehydroascorbate reductase (EC 1.8.5.1; DHAR) plays an important role in maintaining the normal level of ascorbic acid (AsA) by recycling oxidized ascorbic acid. To increase AsA content of potato, we isolated and characterized the cDNAs encoding two isoform DHARs localized in cytosol and chloroplast from potato, and developed two types of transgenic potato plants overexpressing cytosolic DHAR gene and chloroplastic DHAR, respectively. Incorporation of the transgene in the genome of potato was confirmed by PCR and real time RT-PCR. The overexpression of cytosolic DHAR significantly increased DHAR activities and AsA contents in potato leaves and tubers, whereas chloroplastic DHAR overexpression only increased DHAR activities and AsA contents in leaves, and did not change them in tubers. These results indicated that AsA content of potato can be elevated by enhancing recycling ascorbate via DHAR overexpression, moreover, cytosolic DHAR might play main important roles in improving the AsA contents of potato tubers.