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The effects of bagging-induced light reductions on lycopene synthesis and the expression of related genes, antioxidant activity, and sugar composition of ‘Tubtim Siam’ pummelo (Citrus maxima) were investigated. Glucose, ascorbic acid, and flavonoid concentrations and 2, 2-diphenyl-1-picryhydrazyl scavenging activity were decreased in fruit covered with bags while still on the tree [0.01 μmol·m−2·s−1 photosynthetic photon flux density (PPFD)] compared with the untreated control (596.7 μmol·m−2·s−1 PPFD). The bagging treatment significantly decreased the temperatures on the surface in the bag. In addition, the bagging treatment decreased abscisic acid concentrations in the peel and pulp. However, the bagging treatment increased lycopene concentrations, upregulated phytoene synthase (CsPSY) and ζ-carotene desaturase (CsZDS) gene expressions; downregulated chromoplast-specific lycopene cyclase (CsβLCY), β-carotene hydroxylase (CsβCHX), and ε-ring hydroxylase (CsɛCHX); and decreased 9-cis-epoxycarotenoid dioxygenase (CsNCED1) gene expressions in the pulp. It is possible that maintaining a temperature of ≈25 °C in fruit covered with bags may increase the lycopene concentration in the pulp with the upregulation of CsPSY and CsZDS and the downregulation of CsβLCY, CsβCHX, CsɛCHX, and CsNCED1 gene expressions in the pulp.

Lycopene has been broadly studied in recent decades due to its health benefits including cancer prevention, anti-atherogenic and anti-obesity effects, and modulation of the immune system. To obtain efficient synthesis of lycopene, extensive researches have been conducted in various microbial cells, including Yarrowia lipolytica, to heterologously produce lycopene using various genetic and metabolic engineering methods. In this study, the effects of copy numbers of lycopene synthesis genes, a variety of key central metabolic genes (especially AMP deaminase-encoding gene AMPD), and 5-L fermenter cultivation on lycopene production in Y. lipolytica were investigated and the engineered strains with significantly enhanced lycopene content (46–60 mg/g DCW) were achieved. It is therefore possible to make use of the obtained strains to meet the industrial demand of lycopene production on the basis of further genetic and process optimization.

Fermented soybean is abundant in nutrients and bioactive ingredients. Lycopene has been reported to decrease oxidative damage, inhibit tumorigenesis, and protect cardiovascular system. In this study, three key genes (crtE, crtI, crtB) involved in lycopene synthesis were co-expressed in Bacillus amyloliquefaciens HZ-12, resulting in a lycopene producing strain HZ-12/pHYcrtEIB. This strain was used to ferment soybean, and the fermentation conditions were optimized. The highest lycopene concentration (7.3 mg/kg) was achieved at 37 °C and initial moisture content of 60%, and the lycopene endowed the red appearance for fermented soybean. Accordingly, the accumulated lycopene significantly improved the antioxidant activity of fermented soybean. Moreover, the fermented soybean showed potent anticoagulant activity, and the anticoagulant activity almost reached 100% when the concentration of soybean extract was 0.4 mg/mL. This study modified B. amyloliquefaciens to produce a novel fermented soybean food with appealing red color and multiple bioactivities, which provided a new and simple strategy for enhancing the functionality of soybean.

Lycopene is a potent antioxidant and has an anti-carcinogenic activity. However, it still remains technically challenging to formulate lipophilic lycopene as an anticancer drug. This issue was addressed by development of a bacterial carrier for targeted delivery of lycopene. First, Escherichia coli was engineered for lycopene synthesis by pathway engineering. A HER2/neu-affinity domain was subsequently displayed on the surface of the lycopene producer, rendering the strain selectively invasive. Finally, the bacterial carrier was fabricated by permeabilizing the constructed strain to facilitate release of the lycopene cargo. As a result of multiple infections with the bacterial carrier, the growth of HER2/neu-positive breast cancer cells was completely arrested. The result indicates that our proposed strategy is promising and may open up a new avenue of targeted cancer therapy using chemopreventive chemicals.

Grape and cherry tomatoes comprise about one quarter of retail tomato sales in the United States and are also important components in fresh-cut mixed vegetable trays. The latter require low temperatures and packaging which can produce a range of modified atmospheres (MA) to achieve 14 days of shelf-life. Postharvest handling recommendations for good tomato quality do not usually include low temperatures or MA. Storage studies were conducted to ascertain the effect of low temperatures and MA on grape tomato quality. Grape tomatoes (orange-red or more advanced color) can be stored in clamshells for up to 18 days at 5°C and still be of marketable quality if kept cold. Continuous storage at 5°C in air resulted in minimal weight loss (a significant cause of quality loss in grape tomato stored at warmer temperatures), and retention of vitamin C levels, but no lycopene synthesis, and decreased sugar concentrations. However, if fruit were transferred from 5 or 10°C to warmer temperatures (i.e., 20°C), typical chilling injury symptoms (decay, poor color formation) occurred on fruit stored at 5°C but not at 10°C. Controlled atmospheres (CA) of 3 or 10% O2 with 0, 7, 12 or 18% CO2 provided little or no benefit, but were tolerated by grape tomatoes for up to 21 days at 5°C. These results are based on evaluation of visual appearance, discoloration, decay, aroma, off-odors, flavor, and changes in concentrations of lycopene, sugars, vitamin C, ethanol and acetaldehyde. Although not ideal, near-ripe high quality grape tomatoes perform well as components of fresh-cut vegetable trays at low temperatures and under atmospheres not usually recommended for tomatoes.

The aim of this study was to describe the physiology of fruit colour in tomato as affected by salinity and ripening on and off the plant. Chlorophyll and lycopene levels were repeatedly measured in ninety Raf tomatoes over a period of eight days using remittance spectroscopy. Fruits were subjected to three salinity levels and were measured either on or off the plant. The physiology of tomato colour was described by a kinetic model centred on the role of STAY-GREEN proteins (SGR) that was calibrated simultaneously on chlorophyll and lycopene data with a percentage variance explained for of 91%. Lycopene precursor and transcript SGR levels were estimated considerably higher for on-plant than for off-plant ripened fruits which indicates ongoing expression while attached to the plant. There is less inhibition of the lycopene precursor by SGR in on plant ripened tomatoes which results in higher maximum lycopene levels and less chlorophyll breakdown causing residual chlorophyll levels. Effects of salinity treatments on chlorophyll breakdown and lycopene synthesis are small, but higher salinity levels strongly diminish fresh weight. Ripening on and off the plant strongly affects colour physiology of tomato fruit and is described well by the proposed model.