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Marketing of raspberries is limited by their short postharvest life under refrigerated storage (

Black garlic (BG) is obtained by the Maillard reaction under controlled conditions of temperature and humidity. This study describes the traditional processing (TT-BG) and the use of ohmic heating (OH) as pre-treatment (OH-BG) to improve time processing. Physicochemical composition and sensory properties were of particular interest in this study. The OH as a pretreatment causes the hydrolysis of fructans to fructose, which are degraded during storage under traditional treatment conditions (70 °C/94% RH) through the Maillard reaction causing the faster formation of compounds responsible for the color of black garlic compared to black garlic without pre-treatment. This reaction cuts down the time to attain the characteristic color of black garlic from 30 to 12 days. The 5-hydroxymethyl-2-furaldehyde (HMF) content was 3.6 times higher in OH-BG than in TT-BG. The polyphenol content and antioxidant capacity did not show differences between TT-BG and OH-BG, but their levels were superior to commercial sample. Both products (OH-BG and TT-BG) were sweet (36.8 and 31.6 °Bx, respectively) and had an excellent organoleptic acceptance (75 and 70%). These results highlight the potential of ohmic heating pretreatment in reducing the time to obtain good quality BG., Ríos-Ríos was supported by a scholarship from the Consejo Nacional de Ciencia y Tecnología (CONACYT-Mexico).

Storage of guava fruit cv ‘Media china’ at temperatures below 8 °C causes chilling injury associated with changes in cell membrane lipids. The aim of the present study was to evaluate the effects of two temperatures (4 and 10 °C) and three controlled atmospheres (air; 10 kPa O2; 5 kPa CO2 and 10 + 5 kPa of O2 and CO2) on microsomal lipid profiles in ripened fruit or fruit storage during three weeks. The study revealed that chilling injury is associated with a decrease in microsomal membrane volume and microsomal protein and phospholipids content (5%, 47% and 22%; respectively). Also, it was observed a decrease in Monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), Phosphatidylinositol (PI), phosphatidic acid (PA), cardiolipin (CL) contents and a substitution of saturated fatty acids (FA) for unsaturated FA in the microsomal membrane. Importantly, it was found that storing guava fruit 'Media China' at 10 °C under 5 kPa CO2 reduced chilling injury prevalence and increased shelf life, suggesting that these storage conditions maintained membrane functionality. Overall, these results indicate that CI is associated to deep alterations in membrane lipids pathway.

The effects of different chelated glycine calcium solutions on the quality and firmness fruit of guava fruit (Psidium guajava L.) were studied. Five sets of 45 fruits of 'Media China′ guava were submerged in different solutions of Glycine-calcium (Ca-Metalosate®) (0, 0.02, 0.08 and 0.14 M) at vacuum (3.3 kPa) during 10 min, and then stored 20 days at 10°C. Fruit samples were analyzed every five days. The firmness (F), weight loss (WL), visual quality (VQ), total soluble solids (TSS), titrable acidity (TA), and electrolyte leakage (EL) were measured. At the end of storage, TSS, TA and EL did not show significant differences between treatments but the fruit treated with 0.08 M Glycine-Ca presented the highest firmness (3.09±1.18 N) and VQ as well as the lowest WL (9.69%), while control fruit showed the lowest firmness (1.68±1.3 N). The ripening process was not affected by the treatment suggesting that the application of postharvest calcium could maintain firmness and quality of guava fruits.

The mango export market demands varieties with high fruit quality and firmness. The ‘Manila’ mango has high sensory quality, but does not yet reach export markets largely due to high weight loss, shrivel and rapid firmness loss during ripening. Application of 1-methylcyclopropene (1-MCP) alone or combined with a microperforated bag (MP bag) or nitric oxide (NO) alone or combined with waxing were studied for efficacy to delay fruit softening, shrivel and weight loss. The waxing alone or combined with NO maintained fruit firmness up to 18 d at 13 °C and reduced weight loss and shrivel, whereas the MP bag with 1-MCP reduced weight loss and shrivel but firmness was maintained only for 10 d at 13 °C. Treatments applied did not have an effect on color, TSS and TA changes during ripening. Pectinesterase (PE) and polygalacturonase (PG) activities in exocarp tissue were not related to firmness loss. However, in waxed fruit, PE and PG activities in the mesocarp only partially explained the softening process. The weight loss of ‘Manila’ mango is directly related to the shriveled appearance of the fruit, as well as contributing to firmness loss.

Bulb size and regularity of shape and absence of defects determine garlic commercial quality, with these factors being related to variety, environment and cultural practices. Low temperatures and short photoperiods at the beginning of development, followed by high temperatures and long photoperiods at the end of the crop cycle are important for good bulb formation. Conditioning “seed” cloves at low temperatures before they are sown ahead harvesting and also decreases the incidence of undifferentiated bulbs; however, its effects on growth pattern, fructan accumulation and gene expression of enzymes associated with their synthesis are unknown. During 4 different seasons, sets of two hundred garlic bulbs ‘Coreano’ were conditioned at 5 °C (5C) for 5 weeks and others sets were stored at room temperature (RT), the cloves were separated and selected by weight (5–8 g). Three treated replicates, two hundred cloves per replicate, were sown in commercial fields at Cosio Aguascalientes Mexico. Representative samples of plants were analyzed for growth parameters, sugar and fructan contents, and 1-SST expression at different developmental stages. During the conditioning at 5C, the buds of different cloves were used to 1-SST expression. The 5C plants had shortened crop cycle (32–42 days), and their growth rate was higher (0.23 cm d−1) compared to RT plants (0.013 cm d−1). The fructan accumulation was also accelerated, and this process could be associated with leaf senescence, apparently modulated by the high glucose content in leaves of 5C plants (7.7 mg 100 g−1) in comparison with the RT plants (1.5 mg 100 g−1). However, the 5C plants did not reach either the yield or quality features of the RT plants. 1-SST expression was higher in the garlic buds conditioned at 5C than in those of RT plants; however, with respect to plant development, the expression was higher in all organs of RT plants. The conditioning of garlic bulbs at 5 °C was effective in shortening the harvest time and in eliminating the incidence of defects, allowing them to be harvested when the garlic supply is low. The changes in fructan and sugar metabolism influence growth pattern.

The behavior of enteroaggregative Escherichia coli (EAEC), non-O157 shiga toxin-producing E. coli (non-O157-STEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) on mung bean seeds at 25±2 °C and during germination and sprouting of mung bean seeds at 20±2 ° and 30±2 °C and on mung bean sprouts at 3±2 °C was determined. When mung bean seeds were inoculated with EAEC, non-O157 STEC, EIEC, EPEC or ETEC strains, all these diarrheagenic E. coli pathotypes (DEPs) survived at least 90 days on mung bean seeds at 25±2 °C. All DEPs grew during germination and sprouting of seeds, reaching counts of approximately 5 Log and 7 Log CFU/g after 2 days at 20±2 ° and 30±2 °C, respectively. However, when the sprouts were inoculated after 1 day of seeds germination and stored at 20±2 ° or 30±2 °C, no growth was observed for any DEPs during sprouting at 20±2 °C per 9 d; however, a significant increase in the concentration of DEPs of approximately 0.7 log CFU/g was observed during sprouting at 30±2 °C after 1 day of sprout contamination. Refrigeration reduced the number of viable DEPs strains on sprouts after 10 days in storage; nevertheless, these decreases have no practical significance in the safety of the sprouts.

White and purple garlic is harvested in the Bajio region of Mexico from February to August and then stored at room temperature. A complete study of quality changes under different conditions and how these conditions interact to determine the shelf life of the product has been lacking, nor have objective parameters to predict shelf life been determined. Six batches of 360 bulbs of garlic ( Allium sativum L.) cv. Perla were stored for 190 days at 0 °C, 0 °C and 70% relative humidity (RH), 5, 20, 30 °C, and at room temperature (RT) (17.7 ± 7 °C). The weight loss, subjective firmness of the bulbs, clove penetration resistance, hue value, internal sprouting index, soluble solids and dry matter content of the cloves were recorded periodically. The weight loss and internal sprouting index had a negative correlation on the subjective firmness, penetration resistance, and hue of the cloves. Storage at 5 °C, 20 °C, and RT induced sprouting, and subsequent growth had an effect on a loss of firmness and color. Complete sprouting (>100%) induced a weight loss of 9–11% at these temperatures. In order to maintain an adequate safety margin for marketing, we propose an internal sprouting index of 50% to determining the effective shelf life of garlic cv. ‘Perla’. In accordance with this criterion and in conditions studying, shelf life at 0 °C was 155 days; at 5 °C and RT it was 80 days; and at 20 °C it was 60 days. These results lead us to conclude that it is possible to estimate the shelf life of garlic using the internal sprouting index.

Susceptibility of kernels of 11 pecan [ Carya illinoensis (Wangenh) K. Koch] genotypes to infection by Aspergillus flavus Link (strain 7757-3) and A. parasiticus Speare (strain CI 13-3) at 0.86, 0.90 and 0.97 water activity ( A w ) was evaluated. For each genotype, A w , and fungal species, five pecan kernels were inoculated with a spore suspension and incubated at 22–24°C; the test was performed three times at different times. Fungal development was evaluated for time of infection to symptom development (t’SD), time of complete colonization (t’CC), and rate of infection (RI). A. flavus and A. parasiticus showed lower t’SD values at higher A w , but there was a difference between the two fungal species in levels of t’SD values. At 0.97, 0.90 and 0.86 A w levels, means of t’SD were 6.4, 14.4 and 39.9 days, respectively, for A. flavus . The corresponding values for A. parasiticus were 5.2, 10.2 and 22.9 days, respectively. Complete colonization was not reached when kernels were kept at 0.86 A w . Means of RI for 0.90 and 0.97 A w were 0.20 and 0.73 for A. parasiticus and 0.13 and 0.53 for A. flavus , respectively . Although susceptibility of genotype rankings was not always kept, “Wichita” showed superior t’SD as compared to other genotypes at all A w levels for A. flavus . Greater relative resistance to mycelium development in Wichita was also at 0.90 and 0.97 A w for A. parasiticus . RI also differed significantly between tested genotypes at all water activities tested for both of the Aspergillus species. A negative correlation was observed between tannin content and RI by A. parasiticus when kernels were incubated at 0.97 A w . We conclude that A. parasiticus develops faster than A. flavus at all A w levels and for every pecan kernel genotype. Susceptibility to infection by A. flavus and A. parasiticus varied significantly among pecan genotypes studied. Wichita almost always showed more resistance to infection than other genotypes. These results suggest that it is possible to select pecan cultivars for kernel resistance to Aspergillus infection.