Nutritional Quality and Popability of Popcorn (Zea mays L. var. everta) in Response to Compost and NPK 20-7-3 Application under Dryland Condition of South Africa.

The dietary value of popcorn, an important snack, depends on its proximate and nutritional constituents, while the economic worth is based on popability and expansion traits of the kernels. There is paucity of information on how soil fertility influences or relates with popping potentials as well as quality of popcorn kernel in semi-arid region. Therefore, the proximate composition and popping parameters of popcorn in response to organic and inorganic fertilizers were investigated. The field trial was conducted in 2017-2019, and it comprised five amendment rates including 90 and 180 kg ha-1 NPK fertilizer and 4 and 8 t ha-1 compost and unamended treatment as the control. The trial was arranged in randomized complete block design in triplicate. Data on kernel yield, biomass, and harvest index were evaluated. Kernels were analysed for proximate composition and popping indices using standard procedures. Across the two seasons, mean protein (8.1%) and fibre (10.2%) contents were highest in kernels from plots fertilized with NPK at 180 kg ha-1, while grains from plots fertilized with 8 t ha-1 compost had the highest moisture (19.3%) and starch (50.1%) contents. The highest kernel expansion of 54.18 cm3 g-1 and 77.6% popped kernels were obtained in plots fertilized with 4 t ha-1 compost. Most of the kernels (61%) were small-sized caryopsis. Popability is significantly associated with volume expansion (r = 0.696). Proximate components and popability improved greatly in compost-augmented field relative to the unfertilized plots. Application of 4 or 8 t ha-1 sorted municipal solid waste compost to Luvisol enhanced growth and nutritional quality of popcorn. In view of promoting nutrient cycling towards improving soil fertility without compromising environmental health, compost is comparable and a good alternative to fossil-based mineral fertilizers.

Rhus coriaria L. (Sumac), a Versatile and Resourceful Food Spice with Cornucopia of Polyphenols.

In recent years, utilization of Rhus coriaria L. (sumac) is upgrading not only in their culinary use and human nutrition, but also in the pharmaceutical industry, food industry and veterinary practices. This is driven by accumulating evidence that support the ethnobotanical use of this plant; in particular, advanced knowledge of the content of nutritional, medicinal and techno-functional bioactive ingredients. Herein, we discuss polyphenolic compounds as the main bioactive ingredients in Rhus coriaria L., which contribute mainly to the significance and utility of this spice. Most of the antioxidant potential and therapeutic roles of sumac are increasingly attributed to its constituent tannins, flavonoids, and phenolic acids. Hydroxyphenyl pyranoanthocyanins and other anthocynins are responsible for the highly desired red pigments accounting for the strong pigmentation capacity and colorant ability of sumac. Certain polyphenols and the essential oil components are responsible for the peculiar flavor and antimicrobial activity of sumac. Tannin-rich sumac extracts and isolates are known to enhance the food quality and the oxidative stability of animal products such as meat and milk. In conclusion, polyphenol-rich sumac extracts and its bioactive ingredients could be exploited towards developing novel food products which do not only address the current consumers' interests regarding organoleptic and nutritional value of food, but also meet the growing need for 'clean label' as well as value addition with respect to antioxidant capacity, disease prevention, and health promotion in humans.

Bioavailability and health risk assessment of potentially toxic elements in popcorn kernel from sandy loam Ferric Luvisol amended with municipal solid waste compost.

Application of municipal solid waste compost (MSWC) to marginal soil enhances crop growth but could also serve as source of pollutants into agroecosystem. There is scanty report on bioavailability of potentially toxic element (PTE) and the health risk of consuming popcorn kernel harvested from field fertilized with MSWC. Field trial was carried out in 2017-2019 to evaluate bioavailability of PTEs in kernel of popcorn harvested from field fertilized with MSWC. The trial was conducted at the experimental field of North-West University, Mafikeng campus South Africa. The treatments comprised three rates of MSWC including 0 t/ha (unamended, control), 4 t/ha and 8 t/ha arranged in randomized complete block design and replicated four times. One seed of popcorn was sown at 20 × 70 cm spacing per hole of 3 cm depth in a 6 × 4.2 m plot size. Growth and yield data were collected at maturity. Ears were harvested at maturity and the kernels were dried to 12% moisture content. Air-dried kernels (50 g) samples were collected and analyzed for essential mineral nutrient and some heavy metal(loid)s using ICP-MS. Measured concentrations of these heavy metal(loid)s were then used to calculate the health risk for adults and children. The results showed that uptake concentration was in the order K+ > HPO42- > Mg+2 > Ca2+ > Fe2+ > Cr6+ > Zn2+ > Mn2+ > Cu2+(mg/kg). Uptake concentration of metalloids: Al and Pd was significantly higher in the unamended. Bioavailability of PTE was highest in unamended plots. The average daily intake of the PTEs was within the recommended permissible level. The risk index value for oral pathway was < 1 for both adult and children population. Amending Ferric Luvisol with 80 t/ha MSWC enhanced popcorn growth and, concentration of accumulated PTEs in kernels at this rate, cannot pose health risk to both adult and children population.

Complementary nutrient effects of separately collected human faeces and urine on the yield and nutrient uptake of spinach (Spinacia oleracea).

A glasshouse experiment was conducted to evaluate the combined use of separately collected human faeces and urine as fertilizer for spinach (Spinacia oleracea) production. Seven human faeces N : urine N combinations (1 : 7 to 7 : 1) each supplying 200 kg N ha(-1) were evaluated along with sole human faeces, sole urine, inorganic fertilizer and an unamended control. Complementary application of the two resources, human faeces and urine, increased fresh and dry matter yields only in treatments having high proportions of urine. Nitrogen uptake followed the same trend but the opposite trend occurred for P uptake indicating that urine was a better source of N whereas human faeces were the better source of P. Potassium uptake was not influenced by the two resources. The minimal improvement observed in the fertilizer value of human faeces when co-applied with urine suggested that co-application of the two resources may not give an added yield advantage when compared with sole human faeces.

Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa.

The introduction of ecological sanitation (ECOSAN) toilets in South Africa has created opportunities for safer sanitation and recycling of human excreta, as fertilizers, in rural and peri-urban areas. A study was carried out to evaluate the fertilizer value of human urine (0 to 400 kg N ha(-1)) for maize and tomato, compared to urea, in a tunnel house. Dry matter yield of both maize and tomato, harvested at 9 and 10 weeks after planting, respectively, increased with increasing N rate (both as urine or urea) up to 200 kg N ha(-1). Urea reduced soil electrical conductivity (EC) whereas urine increased it. Leaf tissue Na, in both crops, also increased with urine application. A follow-up study was carried out with two crops with contrasting sensitivity to salinity and using a wider range of N application (0 to 800 kg N ha(-1)). The results indicated increased root and leaf dry-matter yield of beetroot (tolerant to salinity) with increased urine rates up to the highest rate of 800 kg N ha(-1), whereas the leaf and root dry-matter yield of carrot, which is sensitive to salinity, peaked at the low urine application rate of 50 kg N ha(-1). Soil EC increased with urine application up to 4.64 and 13.35 mS cm(-1), under beetroot and carrot, respectively. Generally the results showed that human urine compared well with urea as a source of N for crops but optimum rates depend on the sensitivity of the crops to soil salinity, which should be monitored where human urine is regularly used for fertilizing crops.